1907] Rittcr. — California Coast Ascidians. 43 



Branchial Apparatus. — Siphons both distinct, the branchial 

 longer, its six lobes varying from long and pointed to low and 

 broad. Atrial very far back, obscurely six-lobed. Three rows of 

 stigmata, each row on each side containing about twelve long, nar- 

 I'ow oi>enings. Xo considerable area of nnperforated branchial 

 membrane at either end of the sac. Endostyle heavy, tortuous, 

 even in the least contracted specimens. 



Digestive Apparatus. — Intestinal loop rather narrow, hardly 

 broader than the thorax ; stomach elongate globular, smooth- 

 walled : a distinct pyloric section of the intestine, whole intestinal 

 wall containing much brown pigment. Abdomen frequently but 

 hy no means always severed from the thorax in the preserved 

 colony. 



Eeprodiictive Organs. — Only the ovary seen, this consisting 

 of apparently a few large ova situated alongside the posterior end 

 of the intestinal loop. Tadpoles very large, considerably exceed- 

 ing in bulk the adult zooids. The adhesive tubes, and so-called 

 "gemmiparous tubes" especially well developed; of the former 

 three, the seemingly usual number, being present ; of the latter 

 there are typically six, all large, trumpet-shaped and closely 

 crowded. 



The zooids are so much contracted and so opacjue in the single 

 colony of this species that, in spite of much effort, I have been 

 unable to make the examination as complete as desirable. Enough 

 has been determined, however, to forbid its being identified with 

 any species hitherto described. Its distinctness depends rather on 

 the comliination of several characters than on the positiveness of 

 any. For example, the extremely far back position of the atrial 

 siphon would not in itself be a character of sufficient importance 

 to deliar the species from several other members of the genus. 

 When, however, this trait is taken together with the length of the 

 siphon, its rather obvious lobing, it seems to become a good char- 

 acter. The absence of nnperforated areas of branchial membrane 

 at either end of the sac is also distinctive when joined with other 

 trivial characters. The niunber of "gemmipai'ous tubes'' of the 

 tadpole is greater than in the young of any other species of which 

 I have found fiuures of the larvae. 



