CLASSinCATION OP THE TU>'ICATA. 615 



J r Colour yellowish brown C. clurus, y. Dr. (Med.) 



I Colour whitish aud translucent C. cretaceus, t. Dr (Med.) 



2 r Colour violet C. BelleChiaicB,!).^^)!^. (Med.) 



" \ Colour brownish grey 3 



n 



Test not much vacuolated C. Z'rascAii, Herdm. (S. Atl.) 



Test very much vacuolated, darker than last. 



Cphilippinensis, Herdm. (Mai.) 



Family III. POLTCLINID^, Giard, 1872. 



Colony usually massive ; sometimes iucrusting, sometimes 

 lobed or eveu pedunculated. 



Si/sfe7ns o£ various shapes, sometimes very irregular or absent. 

 Common cloacal apertures usually inconspicuous. 



Ascidiozooids always elongated antero-posteriorly, and usually 

 divided into three distinct regions. Branchial aperture 6- or 8- 

 lobed ; atrial aperture often with atrial lauguet. 



Test gelatinous or cartilaginous, sometimes rendered stiff by 

 imbedded sand-grains. 



Branchial sac usually small and not highly developed. Stig- 

 mata usually small. There may be papilliform connecting-ducts 

 but never internal longitudinal bars. 



Dorsal lamina represented by a series of languets. 



Tentacles small and not numerous. 



Alimentary canal extending considerably beyond the branchial 

 sac posteriorly. 



Gonads placed behind the intestinal loop in the postabdomen. 

 Testis represented by a number o£ small spermatic sacs, attached 

 to a large vas deferens. 



Gemmation from the postabdomen, which has the heart at its 

 extremity. 



This very large family* contains about twenty genera (or sub- 

 genera), which may be distinguished briefly as follows : — 



r Branchial sac with wide meshes and no true stigmata. 



\ Pharyngodictyon. 



[ Branchial sac normal 1 



* I cannot follow Lahille in breaking it up into the two families Polycli- 

 nidffi and Aplidid^e ; nor can I employ, as he does, the twisting of the intestinal 

 loop as a primary character in distinguishing the genera; intermediate con- 

 ditions are found between the typical Polyclinid condition and that found in 

 Amarouci'wm. 



LLNN. JOUEN. — ZOOLOGY, VOL. XSIII. 44 



