THE ASCIDIANS 233 



Ganglion very close to the hypophysis opening. Branchial sac with six 

 well developed, nearly equal folds on each side ; six or seven longitudinal 

 vessels on each fold ; none between the folds. No transverse vessels 

 present besides the imperfect septa between the infundibulae. Infun- 

 dibulae deep and rather narrow, the stigmata reaching entirely around 

 them; quite regular in size and arrangement (p1. xxviii, fig. 18). 

 Endostyle narrow. Dorsal lamina a plain broad membrane terminating 

 at the left of the esophagal opening. 



Digestive apparatus. — Esophagal opening at the extreme postero- 

 dorsal angle of the branchial sac. Intestinal loop reaching entirely 

 across the animal ; rather broad at its ventral end, bvit closed together 

 dorsally where the rectal bend comes in contact with the esophagus. 

 Dorsal limb of rectum rather short, running close along the dorsal edge 

 of the animal. 



Esophagus narrow, stomach nearly cylindrical, somewhat longer 

 than thick, set off from the esophagus by an abrupt shoulder, its wall 

 thrown into about ten or twelve distinct, closely approximated, some- 

 what tortuous, longitudinal ridges, of a light yellow color. Intestine 

 from stomach to anus of nearly equal diameter throvighout. Anus 

 unarmed (p1. xxviii, fig. 11). 



Reproductive orgatts. — Present on left side only, and both ovary 

 and testis placed tvithin the intestinal loop, which they completely 

 fill. Ovary occupying the middle; testis in the form of a great num- 

 ber of nearly spherical masses surrounding the ovary and in close 

 contact with the intestine. Ovidvict very short, running along the 

 dorsal side of the rectum (p1. xxviii, fig. 11). 



Renal organs. — Consisting of two small, somewhat elongated, but 

 irregular bodies situated one on each side of the body far back and 

 clinging to the inner surface of the mantle. 



I have not observed the ectodermal processes or papillae on the outer 

 surface of the mantle (p1. xxviii, figs, 19^ and 19^) in any other Asci- 

 dian, nor have I found anything like them described in any other 

 species, though they are undoubtedly homologous with the ectodermal 

 portion of the processes occurring on many species of Molgula. 



They are scattered over the entire surface of the mantle, but are 

 somewhat more abvmdant at the posterior end. Each one consists of 

 a wall of distinct epithelial cells, and a lumen which communicates 

 freely with the body space, and into which the blood passes. The 

 ends are somewhat bulbous owing to the larger size of their epithe- 

 lial cells. 



The peduncle, with its system of rootlets and holdfasts, is a remark- 



Proc. Wash. Acad. Sci., July, 1901. 



