464 Universitu of California Publications in Zoology [Vol.16 



B. diegensis appears to be more like Botrylloidcs purpureum. 

 Herd. (Herdman, 1886) from near the Philippine Islands than any 

 other species. The conspicuous gastric loops are, however, quite dis- 

 tinctive of diegensis. Furthermore, purpureum is described as pre- 

 senting a lobing of the mantle at the branchial aperture which does 

 not occur in diegensis. Again, the transverse musculature of the 

 mantle of purpureum is considerablj^ stronger than that of diegensis. 



Perophora annectens Ritt. 



Peropliora annectens, Ritter, 1893. 

 Perophora annectens, Huntsman, 1011, p. 118. 



A careful study of the asexual reproduction and relation of the 

 zooids in the colony in P. annecten-s relative to its geographic di.stri- 

 bution and general habits of life ought to he made ; for nowhere in its 

 range, as it now seems, excepting in central California, do the colonies 

 reach the complete "compound ascidian" condition described for some 

 specimens by Ritter, 1893. Although the species is by no means rare 

 on the southern coast, we have never found it in any such abundance 

 as that in which it occurs at Pacific Grove, and the zooids are always, 

 so far as our observations have gone, quite di.stinct from one another. 

 Huntsman (1911) reports tlie same to be true of specimens from the 

 coa.st of Briti.sh Columbia. 



Distaplia occidentalis, n. sp. 



Although D. occidentalis has already figured to a considerable 

 extent in writings on ascidians, notably in the paper by Bancroft 

 (1899), it has always appeared, so far as taxonomy is concerned, as 

 a manuscript species by Ritter. But since neither diagnosis nor 

 species-figure have been publi.shed hitherto, its career as a known 

 species ought to date from the publication of this paper, and Ritter 

 and Forsyth recognized as responsible for it (pi. 45, figs. 64 and 65). 



Superficial characteristics of the colony. — Either flat and encrust- 

 ing, or pedunculated and mushroom-shaped with all gradations be- 

 tween; flat, from 3 or 4mm. thick and several centimeters in expanse; 

 pedunculated forms varying from 2 mm. to 1 cm. or more across flat- 

 tened heads, peduncles being of same length or longer; flat form often 

 pedunculated at margins of colonies. Systems plain, several in a 

 head; zooids closely arranged around a large, cylindrical, lobed, 

 common atrial orifice, which extends considerabh^ above the general 



