2 Dr. Asajiro Oka : 



a peduncle by which it is attached to some foreign body. The 

 colony proper or head, which alone is composed of zooids, has the 

 form of a short hollow cylinder, about as long as it is wide and 

 closed at one end where it joins the stalk. Unlike Fyrosoma there 

 is no diaphragm at the open end, so that the terminal aperture is 

 of the same width as the central cavity. The peduncle is short, 

 columnar, and dilated at the lower extremity to form a base of 

 attachment. The entire animal, in consequence, is so perfect- 

 ly cup-like in appearance that I could think of no better 

 generic name than the one given in the title of this paper. 



The zooids forming the wall of the hollow cylinder are 

 arranged in vertical lines which run distinctly in pairs. Looked 

 at from inside each double row of zooids with their common 

 investing mass is found to form a cushion-like longitudinal ridge 

 projecting into the central cavity and separated from its neigh- 

 bours on both sides by narrow deep furrows. The zooids are 

 imbedded in the common test in such a manner that the branchial 

 apertures all open on the outer surface of the colony, and the 

 atrial cavities all communicate directly with the longitudinal 

 furrows just mentioned, which, of course, are nothing but the 

 peripheral portions of the central cavity. There are no definite 

 atrial apertures present, since the wall of the peribranchial cavity 

 is wanting in the greater part of the thoracic region and the 

 stigmata of the branchial sac as well as the anal and genital 

 apertures open immediately into the adjacent longitudinal furrow. 

 Thus the central cavity serves, as in the case of Fyrosoma^ as the 

 common cloaca of the whole colony which may be regarded as 

 consisting of a single system of zooids, but this S3^stem is, in the 

 present case, divided into groups of zooids whose atrial cavities 

 are partly fused together to form a large continuous peribranchial 

 space. 



It is perfectly obvious that a compound ascidian with such 

 characters as those mentioned above can not be included in any 

 of the recognized families, and I consider myself fully justified in 

 forming a new family for its reception. Since, how^ever, only one 

 genus of this family is at present known, I believe it would be of 



