on the Natural Group of Tunicata. 543 



colour I cannot ascertain ; but if it be the same as that of the 

 specimen in spirits, it is cinereous, rather yellowish. The exter- 

 nal orifices have scabrous rims, are very minute and scarcely at 

 all prominent. The branchial orifice is quadrifid, and placed 

 exactly half-way down the side. The anal orifice is on the same 

 line with it and the pedicle, but is placed opposite to this last, so 

 as to be terminal, having its external surface apparently without 

 rays ; in both respects being totally different from the anal orifice 

 of Bolte?iia. 



The entrance of the branchial cavity is provided with a cir- 

 cular range of ten or twelve unequal tentacula, which are com- 

 posite or divided into laciniae at the extremity, which laciniae are 

 again so minutely divided as to be almost plumate. The bran- 

 chial pouch has about fourteen folds, and its net-work is very 

 indistinct and lax, the transverse nervures being perhaps the 

 most visible, particularly towards the branchial orifice. The 

 folds of the branchiae are most easily seen on the inside of the 

 branchial pouch. 



The pharynx is situated rather higher than the branchial ori- 

 fice ; and the esophagus, which is about half the length of the 

 stomach, after ascending to the highest part of the branchial 

 vein, descends, and gives rise to a simple but enormous stomach, 

 having a longitudinal division, marked somewhat deeply, and 

 which runs almost the whole length of the body in a line between 

 the base of the pedicle and the anal orifice. The intestine is 

 exceedingly short, and apparently descending in a line with the 

 stomach ; the rectum is cylindrical, and anus simple. Such, at 

 least, is the description of the digestive apparatus of this animal, 

 if we give the name of pharynx to that end of the intestinal canal 

 which opens into the branchial cavity, and the name of anus to 

 that end of it which is free ; and there is no doubt that such a de- 

 scription makes it an animal totally different from Boltenia, and in 



fact 



