118 BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 



of uniform size. The minute plication of the wall of the sac char- 

 acteristic of most members of the genus is fairly well developed, but 

 the large transverse vessels take no part in it. The plications vary 

 from about half as numerous to nearly as numerous as the internal 

 longitudinal vessels. Internal longitudinal vessels numerous, sepa- 

 rated in one of the largest specimens by five or six stigmata in the 

 narrow anterior part of the sac, but farther back where the sac 

 becomes wider by a larger number, often 10 or 11. In smaller indi- 

 viduals the average number of stigmata intervening between such 

 vessels is generally somewhat less. At the intersection with trans- 

 verse vessels, but net at intermediate points, the internal longitudinal 

 vessels bear curved papillae, which have a membrane along the con- 

 cave border and generally a pair of small rounded projections at the 

 base. The internal longitudinal vessels are often incomplete or 

 interrupted between some of the transverse vessels. 



Digestive tract large and covering an extensive aren on the left 

 side of the body, though its parts are compactly disposed, the rectum 

 ascending quite close along the descending or posteriorly extending 

 part of the intestinal loop. Margin of anus more or less distinctly 

 plicated. 



Ovary composed of a mass of rather stout convoluted tubules. It 

 is partly visible through the mantle, lying in the bend of the anterior 

 part of the intestinal loop, a few of the tubules usually spreading 

 out upon that surface of the intestine which lies next to the mantle. 

 From the ovary the large stout oviduct (usually closely packed with 

 eggs) accompanies the terminal portion of the intestine lying upon 

 it (as seen through the mantle) or along its dorsal border and 

 terminates near the anus. 



The male organ consists of an immense number of small irregularly 

 distributed glands of simple though irregular shape, connected by 

 a system of branching ducts leading to a common sperm duct accom- 

 panying the oviduct. Though the organ lies largely between the 

 digestive tract and branchial sac, parts of it come out upon that sur- 

 face of the stomach and intestine lying next to the mantle through 

 the interval within the curves of the digestive tract, and generally 

 also by reaching around the outer border of the anterior part of the 

 intestinal loop. 



Judging from its representation in the collection, this is one of the 

 commonest and most widely distributed ascidians in the Philippine 

 region. The specimens were collected on the reefs and in shallow 

 water (greatest depth 31 fathoms). They agree well with Heller's 

 (1878) original description and figure based on a specimen from 

 Ceylon, but there is considerable variation, especially in external form 

 and appearance, between different specimens of the series collected by 



