360 PROCEEDINGS OF THE ACADEMY OF 
ON A NEW AMERICAN SPECIES OF PLEURONECTOID {GLYPTOCEPHALUS 
ACADIANUS). 
BY THEODORE GILL, M.D. 
In the " Proceedings of the Academy of Natural Sciences of 
Philadelphia" for 1864 (pp. 214-224), was published a "Synopsis 
of the Pleuronectoids of the eastern coast of North America," in 
which two generic t3'pes, either entirely new {Euchalarodus) or 
new to the coast ( Githarichthyii)^ were made known. The present 
article may be regarded as supplementary to that. 
The only known specimen of the new type was obtained from 
a pond at Eastport, Maine, during the month of August, by an 
attache (Di'. Edward Palmer) of the Commissioner of Fisheries 
(Prof. Baird), and, notwithstanding the assiduous attentions of 
the commissioner and his staff, no other specimens were found; it 
must, therefore, be actually a very rare fish, or (what is more 
probable in such cases) peculiar in its habitat, and rarely coming 
within the range of operations of the fisherman. 
An attentive examination and comparison of this species with 
the Glyptocephalus cynoglossus, of Europe, indicate that it is 
congeneric with that species and with the Platessa elongata of 
Yarrell, but more nearly allied to the latter. As the genus is now 
for the first time introduced into our fauna, a description of the 
characters common to all the species (generic), as well as distinc- 
tive of the new form (specific), is given. 
Genus GLYPTOCEPHALUS, Gottsohe. 
Synonymy. 
Olyptocephalus, Gottsohe, Arcliiv fiir Nat. 1835, i. p. 156; Blkr., Compt. 
Rend. Acad. Sci., Amsterdam, xiii., 1SG2. 
Body oblong fusiform, with the caudal peduncle abbreviated. 
Scales minute, oval, cycloid on the e3'ed as well as blind side, 
and regularl}' imbricated. 
Lateral line straight, with its scales covered on both sides by 
the adjoining ones. 
Head small, ovate, the profile being slightly decurved, and with 
the rostral area rhomboid; covered with minute imbricated scales 
on the cheeks and opercular bones ; on the blind side exhibiting 
NATURAL SCIENCES OF PHILADELPHIA. 361 
fovere or pits in the cranium and preoperculum ; orbital ridge 
prominent, narrow, and curved upwards towards tlie lateral line 
(with no bony tubercles). 
Eyes moderate, approximated, the upper (in typical species) 
somewhat further back than the lower, mostly in the anterior third 
of head. 
Nostrils of the ej^ed side parallel with the axis of the body ; 
the posterior patulous, and above the supraorbital crest ; the an- 
terior tubular, and near tiie border of the snout; those of the 
blind side in an oblique row ; the posterior patulous ; the " ante- 
rior" tubular. 
3Ioufh very small, with the cleft very oblique, deeper and less 
oblique (the supramaxillary being longer) on the blind side. 
Lower jaw scarcely prominent, with a declining obtusely angular 
(not tuberculated) chin. 
Lips moderate and simple, free all around. 
Tongue small and scarcely free. 
Teeth fixed, uniserial, on the blind side approximated and with 
compressed squarish crowns ; on the eyed side (1) similar or (2) 
more distant and obtusely conic. (Palate unarmed.) 
Branchial apertures closed above the opercula, with the mem- 
brane free below. 
Branchiostegal rays seven. 
Dorsal fin with its rays simple, in large number (100-120); with 
its origin above the middle of the upper orbit, with the foremost 
and hindmost rays (when at rest) converging, and the rest erect. 
Anal fin with its rays simple, in large number (90-105), with 
its foremost and hindmost rays converging, but the rest erect; 
preceded in front by a well-defined spur-like spine curved for- 
wards. 
Caudal fin convex or angulated behind. 
Pectoral fins small, obliquely rounded behind, and with branched 
rays. 
Ventral fin subbrachial, normally -developed. 
Type^ Pleuronectes cynoglossus, Linn. 
This genus is well distinguished by the elongated and com- 
pressed body covered by cycloid scales, the straight lateral line, 
the small head with its well-defined foveje (showing through the 
scaly skin) of the cranial and preopercular regions, the numerous 
dorsal and anal rays, and the preanal spur-like spine. Three 
24 
362 PROCEEDINGS OF THE ACADEMY OP 
species seem now to be referable to the genus: (1) the typical 
species {G. cynoglossus = Pleuronectes cynoglossiis, Linn); (2) a 
rare British form (G. elongatiis = Platessa elongata, Yarrell), and 
(3) an luulescribed species peculiar to the Acodian province of 
naturalists (G. acadianus. Gill). These appear to represent two 
sections of the genus; the first species one, and the second and 
third another. 
GLYPTOCEPHALUS ACADIANUS, Gill. 
The height of the body enters about 2| times in the length, ex- 
clusive of the caudal (3^ in the extreme length) ; the height of 
the caudal peduncle is little more than 1^ of its length. The 
head enters 5^ times in the length. 
The teeth are decidedl}' unlike on the respective sides, those of 
the blind side being close set, with incisorial edges, about 17 in 
the upper jaw, and 20 in tlie lower ; those of the eye side distant, 
obtusely conic, 6 in the upper and 7 in the lower jaw. The greatest 
height of the dorsal equals about half the length of the head, as 
does also that of the anal. The caudal fin enters about 5^ times 
in the extretne length. The pectoral fin (of the dark side) is con- 
siderably more than half tlie head's length, and the ventral coii- 
siderabl}' less than half; the base of the ventral is under that of 
the pectoral (but a little further advanced). 
D. 110, A. 100. 
The color is rufous-brown, immaculate. 
The single specimen, from which the above description was 
taken, was apparently not full grown, and, as already remarked, 
was obtained from a net at Eastport, Maine. 
The species is evidently congeneric with, and closelj' related 
to, the G. elongaius (Flalestio elongata), of which an incorrect 
figure is given in Yarrell's work, and (in some respects) a more 
accurate one in Couch's History of British Fishes; it is, however, 
less elongated and the head larger.