CLA.SSIFICATION OF THE TUNICATA. 601 



Brancliial sac minutely plicated ; with iuternal loDgitudinal 

 bars, which are not papillated. 

 Tentacles simple. 

 Heart and pericardium curved into a U-shape. 



This genus contains two species : — 



Branchial aperture 8-lobecl,ati-ial 6 R. neapolifaiia, Phil. (Med.) 



Branchial aperture 6-lobed, atrial 12 ... E. cerberiana, Lab. (Med.) 



Ehopalopsis, Rerdman.l^^O. 

 Body elongated, divided into thorax and abdomen. 

 Test cartilaginous. Apertures not distinctly lobed. 

 Branchial sac not minutely plicated. Internal longitudinal 

 bars present, but not papillated. 



This genus contains the two following species : — 



Test thin anteriorly, dai'k coloured i?. /e^sm, Herdm. (Mai.) 



Test thick all over, light grey R. crassa, Herdm. (Mai.) 



Sltjiteria, Ed. v. Ben., 1887. 



Body short, not divided into thorax and abdomen, united to 

 the stolon by a short peduncle. Apertures botli 7-lobed. 



Test containing blood-vessels terminating in conical papillae. 



Branchial sac not minutely plicated. Many rows of stigmata 

 present. 



Dorsal lamina in the form of a membrane provided with long 

 marginal processes. 



This genus was formed for the reception of the single species 

 aS^. ruhricollis, Sluiter, from the island of Billiton in the Malay 

 Archipelago. 



EcTEiifASCiDiA, ITerdman, 1880. 



Body elongated, usually tapering posteriorly, sometimes with 

 a short peduncle; but not divided into thorax and abdomen. 



Test thin and membranous, containing no blood-vessels. Aper- 

 tures not distinctly lobed. 



Mantle thin, musculature consisting of transverse bands. 



Branchial sac with internal longitudinal bars, but no papillae. 



Dorsal lamina represented by a series of tentacular lauguets, 

 which may be connected at their bases by a narrow membrane. 



Tentacles simple. 



Viscera placed on the left side of the branchial sac, and some- 

 times projecting slightly beyond it posteriorly. 



43* 



