CLASSIFICATIOIS" OF THE TUNICATA. 597 



. Dorsal lamina represented by languets, which may be united 

 by a narrow membrane. 



Tentacles simple, filiform. 



Viscera on either right or left side of branchial sac. Intestine 

 small, posterior to the oesophagus and stomach, and forming a 

 loop open dorsally. Stomach short and wide. 



Gonads forming a round mass situated on the intestinal loop. 



This genus is the aberrant member of the subfamily. It is 

 intermediate in its characters between Ascidia and Corella. It 

 contains tlie two 'Challenger' species Ahyssascidia Wyvillii, 

 Herdman, obtained from the south o£ Australia, at a depth of 2600 

 fathoms, and Ahyssascidia vasculosa, Herdman, obtained in the 

 Antarctic south-west of Australia, from a depth of 1950 fathoms. 

 They differ, amongst other points, in the following : — 



Apertures 12- and 8-lobed, languets separate, Tiscera on 



right side A. wyvillii. 



Apertures 8- and 6-lobed, languets united by membrane, 



viscera on left side A. vasculosa. 



Subfamily C i o N i n ^, Boule, 1884. 



£ody more or less cylindrical, attached by posterior end. 



Test thin and gelatinous, may be modified anteriorly to form a 

 lobe covering the apertures. 



Mantle with the musculature mainly longitudinal. 



Branchial sac provided with internal longitudinal bars. Stig- 

 mata straight. 



Dorsal lamina represented by languets. 



Alimentary canal on left side of branchial sac, extending pos- 

 teriorly to it. 



I use this subfamily in a somewhat different sense from that 

 proposed by Eoule. Keeping Ciona as the typical form, I remove 

 Ehopalaea to the family Clavelinidfe, and I substitute in its place 

 Rhodoso7na, which seems to me to have more aflBuity with Ciona 

 than with Ascidia. 



The two genera are as follows : — 



Test modified anteriorly to form an operculum covering the aper- 

 tures Rhodosoma. 



Test not modified Ciona. 



EnonosoMA *, Ehrenherg, 1828. 

 Body cubical or cylindrical, attached, truncated anteriorly. 



* This is the Clievreulius of Lacaze-Duthiers (1865), the Schizascus of Stimp- 

 son (1855), and the Pera (not Pcra, of Stimpson) and Pcroides of Macdouald. 



