CLASSIFICATION OF TUE TUNICATA. 589 



Htpobytuius, Moseley, 1876 [& Kerdman, 1882]. 



Body cup-sLaped or pyriform, pedunculated, attached. Aper- 

 tures circular, not lobed. 



lest cartilaginous, but soft and thin, thichened in places to 

 form plates. 



Branchial sac not folded, and with no internal longitudinal 

 bars. Stigmata small, rounded, and irregularly placed. 



Dorsal lamina a plain membrane. 



Viscera forming a compact elongated mass on the dorsal edge 

 of the branchial sac. 



This remarkable deep-sea genus contains two species, obtained 

 during the ' Challenger ' Expedition from depths of 2900 and 

 GOO fms. :— 



Body on a long peduncle ; test thickened to form many rounded 

 nodules or plates H. calycodcs, Mos. (N. Pac.) 



Body on a short peduncle; test only thickened to Ibrm a single 

 plate on dorsal edge H. Moseleyi, Herdm. (S. Atl. ) 



Subfamily Ascidiin^, Blerdman, 1882. 



Body usually attached by left side or posterior end. Branchial 

 aperture with at least 8 lobes ; atrial with at least 6 lobes. 



Test gelatinous or cartilaginous. 



Mantle with the musculature forming an irregular network, 

 which is strongest on the right side. 



Viscera on the left side of the branchial sac. 



Branchial sac provided with internal longitudinal bars. Stig- 

 mata straight. 



Dorsal lamina usually a plain membrane, rarely languets 

 {Abyssascidia). 



This subfamily contains 5 genera, as follov;s : — 



/ Dorsal lamina present as a membrane 1 



\ Dorsal lamina represented by languets Abyssascidia. 



1 /Branchial sac recurred posteriorly Phallusia. 



\ Branchial sac straight 2 



£, f Nerve-ganglion close to dorsal tubercle Ascidiella. 



■" \ Ganglion distant from dorsal tubercle 3 



" of Test very hard, thick and stiff Pachychlaena. 



"*\Test soft andflexible Ascidia. 



Phallusia (Sav., 1816), Eoule, 1884. 



Body erect, attached. 

 Test cartilaginous. 



