A REVIEW OF THE FLOUNDERS BELONGING TO THE GENUS PLEURONICHTHYS. By Edwin Chapin Starks and William Francis Thompson, Of Stanford University, < 'alifornia. In the following paper six American species, and one Asiatic species, of the genus Pleuronichthys are described, including two new- ones. Types and cotypes of the new species are deposited in the U. S. National Museum. The distribution of each species is known only so far as specimens at hand indicate, for former records show Pleuronichthys ccenosus (representing four species) to occur along (he entire wesl coast of the United States. The species of the ccenosus group are very well separated geo- graphically, though toward the limits of the area inhabited by each species there is more or less overlapping with areas of neighboring species. Specimens are in the National Museum or in the Stanford University collections, showing the following distribution: Pleuronichthys nephelus, new species, is known only from Puget Sound. Pleuronichthys ccenosus is found from San Francisco to San Pedro, California. Along the great length of coast between San Francisco and Puget Sound a species of this group occurs, but no records indi- cate whether it is Pleuronichthys ccenosus- or Pleuronichthys nephelus, or whether, as is probable, both are found at some point. Pleuronichthys ritteri is known from San Pedro southward along nearly the entire west coast of Lower California, or south to latitude 24°. (Albatross station 3042.) I'll iiron'icltlhijs oci llatus, new species, is known from rather deep water only from near the northern end of the Gulf of California. Pleuronichthys t' the head; anterior bony tubercle overhanging mouth; no teeth on eyed side of jaws. .verticalis. <•'-'. lnterorbital ridge not so high or sharp as described above; anterior I y tubercle not anterior to mouth; minute teeth on eyed side of mandible. d l . Scales less 1 hail 75 in a series below lateral line; color very dark; broad irregular (dutches of dark color with sharp, darker, edges over body and fins; caudal peduncle shorl and deep with the tips <>f dorsal and anal rays almost, or quite, reaching liases of caudal rays; posterior lnterorbital spine very little, or not at all developed nepfa lus. (1-. Scales more than 75; color lighter; caudal peduncle longer; posterior inter orbital spine developed. t '. No bony tubercle developed on anterior end of lnterorbital ridge.. co nosus. <*-'. Two bony tubercles developed on anterior end of interorbital ridge. /'. A spot at about middle of lateral line conspicuously ocellated with milk white; scales from 84 to 91; gill rakers below angle of arch 7 to !) on I In I us . /'-'. A spot on middle of lateral line often present, but not conspicuously ocellated with white; scales from 7!) to SI; gill rakers '.) to I I .ritteri. PLEURONICHTHYS DECURRENS Jordan and Gilbert. This species may bo at once known by the very low origin of (lie dorsal lit) on the blind side of the body, the insertion being below the lower corner of the mouth, and at least nine rays are present on the blind side. Head contained from 'A\ to 3§ in length of body without caudal; depth of body I; to 2. Upper orbit, 2\ to 3 in length of head; max- illary 1 to 11; length of caudal peduncle 4 to 5£; its depth 2\ to 3. Number of dorsal rays 71 to 74; anal rays 4(5 to 49; scab's in scries below lateral line «»0 to 95; gill rakers :> or 4 + 7 to 9. I lend considerably thicker than body; the snout projecting beyond the dorsal contour, but less abruptly than in other species, leaving a broad concave area above it extending behind the eyes. The interorbital ridge bears a rather sharp spine at cither end; the poste- rior one the larger; pointing backward and downward. In front of the anterior one, before the lower eye, is a small blunt tubercle, and behind the upper eve are two blunt but very prominent ones. The eyes arc large and protruding, and the upper one i-> posterior to the lower. The dentition is stronger than Jisual. There are three rows of teeth ou the blind side of each jaw; one on the cyod side of the mandible; none on the eyed side of the premaxillary. No.1744. REVIEW OF FLOUNDERS STARKS LND THOMPSON. 279 The dorsal arises below, or at a level with, the corner of the mouth on the blind side of the head, and about nine rays arc off the median line of the body. The ventral of the oyod side is considerably posterior to that of the blind, and the distance between their inser- tions is contained ten times in the head, or three and one-half times in the upper orbit. The caudal peduncle is longer and more slender than in any other American species in the genus. The scales are small, not imbricated, and somewhat concealed by the skin, especially on the head. The dorsal branch of the lateral line runs back to about ten rays from the last ray of the dorsal, but the .interior branch is entirely lacking in the specimens at hand. The color in alcohol is brownish, sometimes mottled with darker, especially at the middle of the lateral line, and posteriorly at the bases of the vertical fins. The vertical fins are brown, sometimes mottled, and narrowly edged with white. The posterior half of the caudal is dark and edged with white across the tips of the rays. Here described from several specimens from between San Francisco and San Pedro, California, from 8 to 10 inches in length. Measurements of Pleuronichthys decurrens. Length of body without caudal, in mm Depth of body in hundredths of length Length of head Upper orbit, longitudinal diameter Distance across both orbits Length of maxillary Ventral of eyed side posterior to that of blind.. Length caudal peduncle Depth of caudal peduncle , Number of dorsal rays Anal rays Scales, below lateral line, in longitudiual series Gill-rakers on first gill arches 158 54 31 11 15 6. 2 3 5. 5 11 74 4!) 90 4 + 8 4 + 8 PLEURONICHTHYS CORNUTUS Schlegel. This species is apparently most closely related to Pleuronichthys verticalis, having similar dentition; a somewhat similar interorbital ridge and spine (though not nearly so high); and a small number of gill-rakers. It differs from it in the greater number of scales; more numerous rays in the dorsal and anal fins; a smaller upper orbit, and a shorter and more slender caudal peduncle. Head 4 to 4^ in length of body to base of caudal; depth L§ to 2. Upper orbit 'A to 3$ in head; maxillary 1 to •!': length of caudal peduncle 7 to S; its depth 2. Number of dorsal rays 71 to 75; anal rays 52 to 57; scales in series below lateral line 100 to 108; gill- rakers 3 + 5 to 7. The dorsal contour is broken slightly at the eye by the projecting snout as in Pleuronichthys verticalis. The interorbital ridge is moder- ate in height, trenchant and narrow, slightly overhanging the snout, 280 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. 38. but not so much so as in Phuronichihys verticalis. On it are two large prominent spines and a bony tubercle as follows: A large sharp spine pointing outward from the anterior end; a small tubercle in front of the lower orbit: and a large sharp spine pointing straight backward from the posterior end. On the posterior margin of the upper orbit are one or two very small tubercles, and a larger one is present on the anterior margin of the upper orbit. The maxillary extends to the anterior margin of the lower pupil, and is hidden anteriorly on the eyed side by the forward extension of the interor- bital ridge. At the posterior end of the mandible there is a prominent angle. There are no teeth on the o\(h\ side of either jaw, but bands of minute teeth on the blind side of both. The left nostrils are as near or nearer to the right nostrils than to the dorsal fin. The dorsal fin begins at the level of the snout, or a little above, and has six rays on the blind side. The ventral of the blind side is anterior to that of the eyed side, and farther from the ventral median edge of the body. The caudal peduncle is somewhat shorter and not so deep as that of Pleuronicht/n/s vert 'walls. The scales are very small and not imbricated in adults anteriorly. The lateral line has a dorsal branch running back to about the fortieth dorsal ray, but the short anterior branch may be absent or present. The color in alcohol is a light grayish brown, with small leopard-like dark brown spots scattered rather uniformly and thickly over the body and vertical fins. There are no indications of ocellated spots, or of regularly placed light spots such as are found on mo-i of the American species. Among the specimens at hand are sonic colored partially or entirely on both sides. These have; in the latter case, more symmetrical pectoral and ventral fins: the upper eye more nearly on the dorsal outline of the body, and the dorsal beginning on a small free lobe overhanging the left margin of the upper orbit. Here described from numerous specimens from Tsuruga and Aomori, Japan Measurements of Pleuronichthys cornutus. Length of body without caudal, in mm Depth of body in hundredths ol Length Length ol head Longitudinal diameter of upper orbll Distance aero < > ■ • f l» orbits Length ol maxillary Ventral of eyed Ide no tenor to that of blind.. Length of caudal peduncle Depth of caudal pod uncle Number Ol dorsal rays Anal rays Scales, below lateral tine, in longitudinal series Gill-rakers on first gill arches 1 15 55 24 10 r. 1.5 12 7.". 54 100 3+6 3+6 No. 1744. REVIEW OF FLOl VDERS STARKS \\l> THOMPSON. 281 PLEURONICHTHYS VERTICALIS Jordan and Gilbert. This species may be known from all others of its genus by its prominent interorbital spines, its greater anterior projection of the interorbital ridge and bony tubercles over the tip of the snout, by its fewer gill-rakers, and from all American species by its having no teeth on the eyed side of either jaw. Head 3| to 4 in length of body without caudal; depth, If to 2\. Upper orbit, 2^ to 3 in head: maxillary, 4 to 5; length of caudal pe- duncle, 5 to 6; its depth, If to 2. Number of dorsal rays, 68 to 71; anal rays, 45 to 4S; scales, 88 to 96 in series below lateral line; gill- rakers, 2 or 3 + 6 or 7. Dorsal outline broken at upper orbit by the projecting snout. The interorbital ridge high and anteriorly is continued so that it overhangs the snout, its anterior edge being almost vertical. On it are two prominent spines; the anterior one between the anterior thirds of the orbit, pointing upward and outward; the posterior on the end of the ridge, larger and sharper than in any other species, and pointing almost straight back. It is above the surface of the head a height equal to 1 diameter of the pupil. On the anterior end of the ridge, in front of the lower eye, is a bony tubercle, and on the pos- terior margin of the upper eye are three conspicuous blunt ones. A trenchant short ridge forms the anterior ed^e of the upper orbit and bears a short tubercle just in front of the eye. There are small teeth in bands on the blind side of both jaws, but none on the eyed side of either. The upper eye is considerably posterior to the lower, and the orbits are somewhat larger than in other species. The maxillary is concealed by the overhanging bony tubercle for the greater part of its length. The dorsal fin arises on a level with the snout, and has five or six rays on the blind side. The insertion of the ventral on the eyed side is posterior to that on the blind a fourth or a fifth of the diameter of the upper orbit. The caudal peduncle is rather long; measuring from the base of the last anal ray to that of the lower caudal ray its length is contained five or six times in the head. The scales are small, and are scarcely imbricated, especially toward the sides of the body. The dorsal branch of the lateral line extends back to under the middle of the dorsal, but the anterior branch is usually lacking in the adult. The color in alcohol is uniform light brown with blotches of darker faintly shown near the middle of the lateral line, and at the ba.se of the caudal peduncle. The vertical (ins are mottled with large brown spots. Here described from five specimens from San Francisco and from southern California, from 6 to !) inches in length. 282 I'ltovEKimtQB OF tin: \ IT10NAL si:i \i. vol. 38. Measurements of Pleuronichthys verticalis. Length of body without caudal, in mm Depth of body in hundredths of length Length of head Longitudinal diameter of upper orbit Distance across both orbits Length of maxillary Ventral of eyed side posterior to that of blind... Length of caudal peduncle Depth of caudal peduncle Number of dorsal rays \iial rays Scales, below lateral line, in longitudinal series. Gill-rakers on first gill arches 220 54 25 9 10 5.5 2 5 14 70 48 96 3+6 3+6 PLEURONICHTHYS NEPHELUS Starks and Thompson, new species. This species has a lower number of scales than any other of the geuus; its low interorbital ridge is free from spines; and the ventral of its cv< i d side is not so far posterior to its fellow of the opposite side. From Pleuronichthys ccenosus it may be known in addition by the smaller diameter of the upper orbit. Head from 3£ to 4 J in length of body without caudal; depth If to 2. Upper orbit 3 to :\h in head; maxillary 3^ to 4; length of caudal peduncle measured to marginal caudal rays 7 or 8; its depth 1£ to 2. Number of dorsal rays 66 to 75; anal rays 47 to 56; scales in series below lateral line 66 to 75 ; gill-rakers 3 or 4 + 9 to 1 1 (in one specimen 12). Body very symmetrical in dorsal and ventral contours, which are evenly curved from caudal to tip of snout. The interorbital ridge is low and without prominent spines; at the anterior end are sometimes very slight indications of tubercles, and the position of the posterior spine i- marked by little more than a slight angle, except in the type (the Largest specimen) there is a blunt tubercle. The eyes are small, not vei \ prominent, and nearly opposite to each other. The nostrils of the left side are close to the dorsal, and those of the right are not so far removed from those of the left as usual. The maxillary is not covered by the preorbital bones. There is a row of teeth on the v \ side of the mandible, but none on the preinaxillary of that side, and three or four rows on the blind side of each jaw. The dorsal tin arises a little above the level of the tip of the snout. The dorsal and anal extend so close to the base of the caudal that the tips of their last rays nearly or quite reach to the bases of the marginal caudal rays. The ventrals are more nearly opposite to each other in insertion than in other species of the genus; the distance of that of the vycA side behind that of its fellow of the opposite side is con- tained three or four times in the length of the maxillary. The caudal lin is very conspicuously broad and round in outline. The scales are large and unimbricated over the entire body, some- times much buried in the skin, the lateral line ascending less than Usually anteriorly, with a short anterior branch, and a long posterior one ending under the middle of the dorsal. No. 1744. REVIEW OF ll.oi \hi:i;s 8TARKS \\l> THOMPSON. 283 The color in alcohol is dark olive mottled with irregular darker blotches sharply cut and darker toward their edges. A black spot, as large as the eye, indistinctly ocellated is present on the middle of the lateral line. On the caudal is a larger, round, dusky spot ; a dark bar across the base of the rays, and the balance of the I'm mottled and edged with white behind. The vertical tins are irregularly mottled and very narrowly edged with white. Here described from twelve specimens from Pugel Sound, Wash- ington. The type is 1(H inches in length, and was collected among the San Juan Islands near the northern end of the sound. It is deposited in the U. S. National Museum. The cotypes are from <> to Fig. 1. — Pleuronichthys ^ethklus. 9 inches in length, and except two, which are from near Seattle, are from the same locality. They are deposited among the collections of Stanford University. Measurements of Pleuronichthys nephehts. Body length withoul cau- dal, in mm Body depth in hundredths of length Length of head... Longitudinal diameter of upper orbit Distance across l>oih orbits. Lengl h of maxillary Ventral of eyed side pos- terior to that of blind Lengl h of caudal peduncle . I >epl h of caudal peduncle. . Number Of dorsal rays Number of anal rays Scales below lateral line In longitudinal series Gill-rakers < 188 23 7.4 in 6. 5 2 3. 5 11 72 50 75 3+KI 3+ 9 1 55 .-,1 24 8. I 11 6. 5 1.5 3. 5 13 68 19 71 3 f lo 3 . 9 1 33 52 24 8,3 12 6.5 1 5 3. 5 13.5 69 17 68 H 10 ; LO 1 25 50 26 7 11 7 1.5 2 13. 5 70 19 3 in 3 i 8 171 52 24 7. 3 in (i 1.5 3 13 68 17 :; | in 10 160 52 23 8 in 7 i. ., 11 66 17 69 3 'i I 'i L63 ■Id 24 8 in ti 1.5 I i 13 72 49 77, 3 ! 9 3 I 9 111 52 22 7.7, 11 6 i ■ 2. 5 15 68 is 70 3 ' in 3+11 130 .-,ii 24 8 11 6. 5 1.2 3 13 69 7,11 65 3-1 in 3 t in 215 -in 25 7.7) 10 6.5 1.5 :; ', 77, 56 70 3 I II 3+11 loo .'.). .) 8. 1 in 6.5 ■> 2 l"( 67 7,1 I I o 124 27 •' 9.1 12 1.7, :; II 70 49 77> l 12 ■nil 284 PROCEEDINGS OF THE NATIONAL MUSEUM. vol 38. PLEURONICHTHYS CCENOSUS Girard. This species differs from PleuronichtJiys ritteri in having no bony tubercle on the anterior end of the interorbital ridge ; a greater number of dorsal and anal rays; a greater number of scales; a shorter dis- tance across both orbits; a shorter caudal peduncle; a lower, more symmetrical, dorsal, and ventral outline of body; a less abruptly protruding snout ; and (in the specimens at hand) in having the usual spot at the middle of the lateral line absent. Head 3 to 4 in length of body without caudal; depth 2. Long diameter of upper orbit 2§ to 3£ in head; maxillary 4; length of caudal peduncle to base of lower caudal rays 8 to 8J; its depth 2. Number of dorsal rays 70 to 74; anal rays 50 to 5.3; scales in series below lateral line 80 to 91 ; gill-rakers 4 + 10 or 1 1 . Body oval in outline, the curve symmetrical with the snout scarcely projecting as it does in Pleuronichihys ritteri. There is a prominent angle at the posterior end of the mandible. The interorbital ridge is rather high and without spines save for a rather blunt one at the posterior end pointing backward and somewhat downward. Behind the upper eye is a small blunt tubercle not very prominent. The nostrils of opposite sides are three times as far apart as from the dorsal fin. There are three or four rows of teeth on the blind side of each jaw, and one row on the eyed side of the mandible, but no teeth on the eyed side of the preniaxillarv. The dorsal is inserted just at, or a little above, the level of the point of the snout, and about six rays are on the blind side. The right ventral is posterior to the left a fourth or a fifth of the long diameter of the upper orbit, and nearer to the ventral ridge than its fellow. The caudal peduncle is short and deep; measured to the marginal caudal rays its length is contained eight times in the head. The scales are small, nowhere closely imbricated, but much less so in large individuals than in small ones, especially along the outer margins of the body. The lateral line has a short branch running anteriorly, and a longer one running posteriorly along the base of the dorsal fm to opposite its middle. Color in alcohol dark brown with mottled, blended spots, slightly darker in color, especially at the middle of the lateral line, at the l>ase of the caudal, and at the bases of the vertical tins posteriorly. A slightly dusky blotch is present on the caudal fm. The blended dusky blotch at the middle of the lateral line is not conspicuous as in /'/< wronicMhys ritteri. Here described from specimens from San Francisco and San Pedro, California, from S to L'U inches in length No. 1744. REVIEW OF FLOl NDERS -STARK8 I \ /> Tllo \l l's< >\ . Measurements of Pleuronichthys ca ho.sux. 2sr> Length i if body without caudal, in mm Depth of body in hundredths of length Length of head Upper orbil (longitudinal diameter) Distance across both orbits Length of maxillary Ventral of eyed side posterior to that of blind Length of caudal peduncle l >t'pt h of caudal peduncle Number of dorsal rays Number of anal rays' Scales in longitudinal series below lateral line Gill-rakers on first gill-arches 265 53 26 8. 5 11 7 2. 3 1. 5 It 78 53 80 3 1 '.) 4 + 8 PLEURONICHTHYS OCELLATUS Starks and Thompson, new species. The nearest relative of this species is Pleuronichthys ritteri, from which it may be known by the presence of a very conspicuous spot Fig. 2. — Pleuronichthys ocellatus. ocellated with milk white midway on the lateral line between the base of the caudal and the snout; by its fewer number of gill-rakers; its greater number of scales; the greater long diameter of its upper orbit, and its interorbital spine a little higher, sharper, and less inclined to bend downward. Head from 3§ to 4| in length of body without caudal; depth '_> to 2\. Long diameter of upper orbit '1 to "J, 7 ,, in head: distance across both orbits two in head; length of maxillary '.\\ to 1; length of caudal peduncle, measured to marginal caudal rays, from (i to 7 1; its depth two. Number of dorsal rays from 61 to 7'_ > ; anal rays 11 to 50; scales in series below lateral line from 84 to 91; gill-rakers 3 or 4 + 7 to 9. The dorsal contour of body outlines broken conspicuously at the upper orbit by the projecting snout. The interorbital ridge is trenchant, narrow, and rather low. The spine on its posterior part •J sc, PROCEEDINGS <>l THE \ L770A W. MUSEl I/. vol. 38. is rather low, and points straight backward. On its anterior end, close together, are two tubercles above the front of the lower eye; on the posterior margin of the upper orbit are two blunter, less con- spicuous ones; a very small one is on the anterior margin of the upper eye. The eyes are large and protruding, and the upper one is posterior to the lower. The left nostrils are remote from the base of the dorsal fin, but nearer to it than to the ri^ht nostrils. The maxillary reaches nearly to the anterior margin of the pupil. There is one row of very minute teeth on the eyed side of the lower jaw, and closely set, small hands on the blind side of both jaws, hut none on t he premaxillary of the eyed side. The dorsal I'm springs from, or slightly above, the level of the tip of the snout, with live or six rays on the blind side. The anal and dorsal are equal in height, the longest ray is contained seven times in the length of the body. The ventral of the eyed side is much posterior to that of the blind, and at a considerable distance from the ventral body ridge; The scales are small and imbricated over the whole body, or at least in contact with each other. The lateral line has a dorsal branch running back from the head to about the thirty-fifth dorsal ray. and a short anterior branch is usually present. The color in alcohol is uniform light brown on the eyed side, with a very prominent dark brown spot ocellated with milk white at the middle of the lateral line. A very inconspicuous, similar spol is at the base of the dorsal and anal fins posteriorly. Spots of white of irregular size, but very indefinite, are scattered over the body, especially along the bases of the vertical fins. Here described from nine specimens from Albatross stations 3027 and 3024, in the Gulf of California. The type is from the latter station, and is 6 inches in length. It is deposited in theU. S. National Museum. Cotypes from the same locality in the National Museum have been examined (Hi specimens examined altogether). Other cotypes are deposited in the collections of Stanford University. Measurements <>r Pleuroniehthys ocellatus. Length in mm. of body without caudal Depth of body in hundredths of body length Length oi head Longitudinal diameter of upper orbil Distance across both orbits Length <>f maxillary Ventral of i posterior to that of blind Length of caudal peduncle Depth of caudal peduncle Number oi dorsal rays Inalrays i in longitudinal series below lateral line '" Gill-rakers mi first gill-arches lis No.1744. REVIEW OF FLOUNDERS STARKS I \ /> T II < > \l l's< >\ 287 PLEURONICHTHYS RITTERI Starks and Morris. This species is more nearly related to Pleuronichihys <>cill to 2\. Number of dorsal rays from 61 to 68; anal rays 45 to 46; scales in series below lateral line, 7!) to 84; gill-rakers, 4 to 6+10 to 11. Body more strongly curved than in Pleuronichihys ccenosus, the dorsal curve broken at the middle of the upper eye by the projecting snout, though less so than in Pleuronichihys oceUatus. The inter- orbital ridge is lower than in Pleuronichihys ccenosus, with two tubercles at the anterior end, and a low conical spine on the posterior end pointing posteriorly and slightly downward. On the posterior margin of the upper orbit are two small tubercles, and on its anterior margin a smaller one. The upper jaw has no teeth on the eyed side. There are three or four rows on the blind side of each jaw, and one row on the eyed side of the mandible. The nostrils of the blind side are closer to the base of the dorsal lin than in Ph uronichthys <>c< llatus. The dorsal fin arises on, or a very little below, the level of the tip of the snout. The ventral of the vyed side is inserted posterior to that of the blind side a distance equal to one-half of the length of the maxillary. The scales are imbricated except opposite the middle of the dorsal and anal fins, where they arc usually separated and somewhat embedded. The lateral line has a short anterior branch, and a dorsal branch running posteriorly to under the middle dorsal rays. The color in alcohol is dark brown with a small dark spot the size of the pupil, or a little larger, slightly posterior to or at the middle of the body, and two larger, more distinct spots opposite to the posterior fifth of the dorsal and anal fins at the base of the rays. Here described from six specimens from San Diego (the type and cotypes) from 4^ to 10 inches in length." Measun rru nts of I'll uronichthys ritteri. Length of body without caudal, in nun Depth of body in hundredths of length Length of head Longitudinal diameter of upper orbit in tance across both orbits Length of maxillary Ventral of eyed side posterior to that of blind Length of caudal peduncle to marginal caudal rays . Depth caudal peduncle Number of dorsal rays Number of anal rays Scales in longitudinal .vries below lateral line Gill-rakers 127 52. 7 26 8. »; i» i,. i ;i :. 12 f, 84 5 II i, ■ II ^Original described in University of California Publications, vol. \\, 1907, p. 243, Contr. to Lab. of Marino Biological Association of San Diego, XVI,