38 BULLETIN SOUTHERN CALIFORNIA ACADEMY OF SCIENCES VOLUME 75 Isaacson. P. A., and D, M. Isaacson. 1966. Notes on the life history of the black perch. Einhiotoca jacksoni Agassiz, Trans. Amer. Fish. Soc, 95: 107-109. Liem, K. F. 1963. Comparative osteology and phylogeny of the Anabantoidei (Teleostei, Pi- sces). Ill, Biol. Monogr.. 30:1-149. Rechnitzer, A. B., and C. Limbaiigh. 1952. Breed- ing habits of Hyperprosopon aigenteum, a vi- viparous fish of California. Copeia, 1952:41-42. Smith. J. G. 1964. Notes on the life history and a description of the sharpnose seaperch, Plianero- don atripes. California Fish and Game, 50:42- 47. Smith, C. L., and R. M. Bailey. 1962. The subocular shelf of fishes. J. Morphol., 110:1-10. Starks, E. C. 1926. Bones of the ethmoid region of the fish skull. Stanford Univ. Publ., Ser., Biol. Sci., 4(3):139-338. Tarp, F. H. 1952. A revision of the family Embio- tocidae {the surfperches). California Dept. Fish and Game, Fish Bull., No. 88, 99 pp. Triplett, F. L. 1960. Notes on the life history of the barred surf-perch, Ainphistichus argcnteus and a technique for culturing embiotocid em- bryos. California Fish and Game, 46:433-439. Accepted for publication April 4, 1975. SPATHIPORA MAZATLANICA. A NEW SPECIES OF BURROWING BRYOZOA (CTENOSTOMATA) FROM MAZATLAN, SINALOA, MEXICO John D. Soule and Dorothy F. Soule^ Abstract: A new species of burrowing Bryozoa (Ctenostomata) from Mexico, Spathipora mazatlanica, is described and illustrated. The polypide anatomy of the genus Spatliipora is determined for the first time. Although the genus Spathipora was erected by Fischer in 1866 from material collected off the French Mediterranean coast, confirmation of its bryozoan ctenostomatous affinities, in general, was not made until the work of E. Marcus ap- peared in 1938. The specimens of Spathipora available to Marcus from Baia de Santos, Brazil had evidently suffered considerable cytolysis, since he was only able to show the cuticle, with the general morphology of the autozoid, and the at- tachment of the stolon close to the proximal (caudal) extremity of the zoid. Marcus also de- scribed the anatomical features of Terebripora ramosa d'Orbigny collected from the same locality, and established that the point of attachment of the stolon to the zoid was about midway between the apertural (distal) and caudal (proximal) extrem- ities, more often closer to the apertural rather than the caudal end. Subsequent work by Soule (1950, 1963), Soule and Soule (1968, 1969a, 1969b), and Voigt and Soule (1973) has con- firmed the Terebripora stn.ictural plan. Silen (1946, 1947) erected two new genera of burrow- ing bryozoans, Immergentia and Penetrantia, and described their anatomy. In material collected at Mazatlan, Mexico in 1973 we have found well preserved zoaria of Spathipora. The anatomical details of Spathipora are available for the first time from whole mounts and serial sections, and comparisons can be made with those burrowing bryozoans whose structure is well known. FAMILY TEREBRIPORIDAE D'ORBIGNY 1847 Genus Spathipora Fischer 1866 Spathipora mazatlanica, new species Holotype. 1976 A NEW BURROWING BRYOZOAN FROM MEXICO 39 d- Fif;iirc I. Photomicropriiph of ihc iracings of SiHtlliipma iiuizuilonna. new species, on llic mollusc shell surface, Photographeil x 50. F/V«/v 2. Scanning electron microscope photo- micrograph of an epon cast of a zoiJ of SiHiiliii'ont. Photographed X -00. 40 BULLETIN SOUTHERN CALIFORNIA ACADEMY OF SCIENCES VOLUME 75 100 m Figure 3. Drawing of a zoid of Spathipora showing proximal attachment, communication tubules and internal anatomy. Figure 4. Drawing of a reproductive zoid with embryo and degenerate polypide. C, communication tubules; D, diaphragm muscle; E, embryo; G, gizzard; O, degenerate polypide; P, parietal muscle; R, retractor muscle; S, stolon; T, tentacles; V, vestibular muscle. Etymology. 1976 A NEW BURROWING BRYOZOAN FROM MEXICO 41 as regular, feather-like (pennate) tracings, with aper- tural openings alternating from one side to the other of the primary and secondary stolons (Fig. 1). Aper- tural openings are irregularly ovoid to key-hole shaped in morphology, narrowed at the edge facing the stolon. These openings are from 50 to 60 /^m in diameter. Material studied was transferred directly to formol- seawater as it was collected. Even short exposure to air causes cytolysis. Some colonies were decalcified in 5% trichloracetic acid for use in whole mounts that were stained with azocarmine, and for serial histological sections. Epon casts were made of other colonies based on the techniques of Hillmer (1968) and Pohowsky (1974) for examination by scanning electron microscopy. Zoids are moderate in size, cy- lindrical, slightly curved and tapering to a single, or occasionally double, knob-like proximal termination. In position, the zoids lie almost parallel to and im- mediately beneath the outer surface of the mollusc shell (Fig. 2). The primary and secondary stolons often have short blind extensions which reach the free surface of the mollusc shell, giving the stolons an undulating pattern. The zoids of Spathipora also possess short lateral accessory tubules that extend to the surface of the mollusc shell (Fig. 3). They are found in a linear series along the abanal wall of the zoid, and range in number from a single communication tubule to as many as eight on a zoid. The stained whole mounts and serial sections show these communication tubules to be hollow, highly cellular in their basal regions, and capped by a keratinized cuticle. Their function is uncertain; possibly respiratory or excretory exchange occurs there between the zoid and the sea water. Anatomically, the polypide consists of eight ten- tacles and a digestive tract of which the most dis- tinctive feature is a prominent gizzard with chitinized denticles. The musculature consists of a set of re- tractor muscles located proximally, parietal muscles positioned laterally, and two pairs each of diaphragm muscles and vestibular muscles in the apertural re- gion. The whole mounts and sections also reveal Ihe presence of zoids with brown bodies. Reproductive zoids (Fig. 4) were relatively rare and scattered at random throughout the colonies. The reproductive zoids ranged from 375 to 450 ^m in length and 100 to 115 ^m in width. Each possesses a prominent ovoid egg or embryo dislally: a degen- erate polypide lies proximally. Measurements. 42 BULLETIN SOUTHERN CALIFORNIA ACADEMY OF SCIENCES VOLUME 75 . 1963. Results of the Puritan- Ammc2ia Museum of Natural History Expedition to West- ern Mexico. 18 Cyclostomata, Ctenostomata (Ectoprocta) and Entoprocta of the Gulf of Cali- fornia. Amer. Mus. Novit., 2144:1-34. Soule. J. D., and D. F. Soule. 1968. A new species of Terebripora (Ectoprocta Ctenostomata) from Antarctic Cephalodiscus. Bull. So. California Acad. Sci.. 67:178-181. . 1969a. Systematics and biogeography of burrowing bryozoans. Amer. Zool., 9:791-802. . 1969b. Three new species of burrowing bryozoans (Ectoprocta) from the Hawaiian Is- lands. Occas. Paps. California Acad. Sci., 78:1-9. Voigt, E., and J. D. Soule. 1973. Cretaceous bur- rowing bryozoans. J. Paleo., 47:21-33. Accepted for publication March 10, 1975. VARIATION IN THE SOUTH AMERICAN COLUBRID SNAKE TANTILLA SEMICINCTA (DUMERIL, BIBRON, AND DUMERIL), WITH COMMENTS ON PATTERN DIMORPHISM Larry David Wilson^ Abstract: Variation and distribution of Tanrilla seinicincta are discussed. This species exhibits pattern dimorphism. One phase has a banded dorsal pattern and the other a striped dorsal pattern. Variation in scutellation is described. This species is known to occur along the Caribbean coastal regions of Colombia and Venezuela. Purported occurrence of this snake in Panama is discounted. Relationships of T. seinicincta with other banded species of Tantilla are discussed and a key to those species is provided. Little information is available concerning the spe- cies of Tantilla occurring in South America. This paper is the first in a series dealing with the taxonomy and distribution of the species of Tan- tilla known from that continent. Tantilla seinicincta (Dumeril, Bibron, and Dumeril) is one of the few species in the genus with a banded dorsal pattern. Only three other species, T. anmdata, T. shawi, and T. siipracincta, have such a pattern. Scolecophis atrocinctus, an apparent close relative of Tantilla (Stickel, 1943), has a pattern very similar to that of T. seinicincta. Tantilla seinicincta is also the only species in the genus known to exhibit a pronounced pattern dimorphism. Tantilla mekmocephala has been re- ported to exhibit pattern dimorphism (Roze, 1966), some individuals having a dark middorsal stripe, whereas others lack it, but it has been suggested that T. inelanocephala, as currently conceived, may be a composite taxon (Schmidt and Walker, 1943). This problem is presently under investigation. PATTERN DIMORPHISM AND VARIATION IN TANTILLA SEMICINCTA Boulenger (1896) was the first worker to note the pattern dimorphism in T. seinicincta, and he did so in passing by placing Hoinalocranion line- atiim Fischer in the synonymy of T. seinicincta and noting the different patterns in his description of the species. Pattern Dimorphism.