.CATALOGUE OF TUNICATA. 71 



, Do., var. rubida, Bass Str. 



Distoma dcerata, Sluit., Torres Str. 



? Chondrostachys sp., Macd., Bass Str. 



? Polyclinum cyliiulricmn, Q. and G., Port Western.] 



Family II. POLYCLINID^!, Giard, 1872. 



Colony usually massive ; sometimes encrusting, sometimes lobed or 

 even pedunculated. 



Systems of various shapes, sometimes very irregular or absent. Com- 

 mon cloacal apertures usually inconspicuous. 



Ascidiozooids always elongated antero-posteriorly, and usually divided 

 into three distinct regions. Branchial 6- or 8-lobed ; atrial aperture 

 often with atrial languet. 



Test gelatinous or cartilaginous, sometimes rendered stiff by imbedded 

 sand grains. 



Branchial sac usually small, and not highly developed. Stigmata 

 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 post-abdomen. Testis 

 represented by a number of small spermatic sacs, attached to a large vas 

 deferens. 



Gemmation from the post-abdomen, which has the heart at its 

 extremity. 



Of the many genera in this family only three are represented. One 

 of these Psammaplidium includes the colonies encrusted with sand. I 

 think it best to refer all the forms with smooth stomachs to Polyclinum, 

 and the rest to Amaroucium. 



Amaroucium, M. Edw., 1841. 



The following four species seem to be new, and probably belong to 

 this genus. 



Amaroucium rotundatum, n. sp., PI. Pel. I., tigs. 14. 



External appearance. The colony consists of a short, stumpy peduncle, 

 which bears a large, somewhat hemispherical mass, the Ascidiarium, 

 placed with its convex surface uppermost (PL Pel. I., tig. 1). The 

 peduncle is very thick and solid. It is of a dark grey colour and is in 



