1907] Bitter. — California Coast Ascidians. 19 



than the atrial, and considerably narrower at the end, making 

 an ill-defined branchial siphon. Surface very uniform and en- 

 tirely free of foreign bodies. Color milk-white, uniform through- 

 out. Test semi-cartilaginous, opaque, from one to two or more 

 mm. thick; from its inner surface a filmy, half gelatinous, irreg- 

 ularly areolated layer readily separates. Mantle rather thick 

 and heavy, its nuisculature consisting of especially large, regular, 

 slightly separated muscle bands, the circular bands being largest. 

 Both mantle proper and its muscles nnich reduced on the ventral 

 side making the viscera, the gonads in particular, distinctly 

 visible through the mantle. 



Branchial Apparatus. — Branchial orifice distinctly four-lobed, 

 atrial situated at the large posterior end of the cylindrical body, 

 making a siphon scarcely recognizable. The test duplicature 

 turned into the branchial siphon of considerable thickness and 

 remaining with the test when the latter is removed from the 

 animal. Tentacles unequal in size, sparsely and irregularly 

 branched, few in number, about ten or twelve. Peripharyngeal 

 band strong, very close to the tentacular circle. Hypophysis 

 horse-shoe shaped, longer than broad, opening turned outward 

 for about one-fourth of a circle; horns not spirally coiled but 

 bent slightly inward. Dorsal lamina a broad area scarcely 

 projecting into the branchial chamber though its two edges are 

 raised into slight folds. Branchial memhrane with six folds on 

 each side, the second to fourth incluse very large ; about five or 

 six longitudinal vessels on each face of each of the prominent 

 folds. Stigmata rather narrow, regular, longitudinal. 



Digestive Tract. — Intestinal loop long, narrow, simple, situ- 

 ated on left side of body, both esophagus and anus near the atrial 

 siphon, and the axis of the loop placed nearly parallel to the 

 endostyle. Esophagus short and narrow, forming nearly a semi- 

 circle. Stomacli but little thicker than intestine and not clearly 

 set off from latter (less so than figure indicates). Wall with 

 many inconspicuous longitudinal folds. A peculiar bulb-like 

 inflation in the rectum near the anus. 



Gonads two, one on each side, the left within the intestinal 

 loop. Ovary cylindrical, regular, constituting an axial part, 

 around which the uniformly sized, crowded testis lobes are dis- 



