ECTEINASCIDIA AND THE CLAVELINID^E. 161 



-.of Stolons united in a basal mass of test (Stereoclavella) 14 

 (Stolons distinct, delicate and branched (Clavelina) 15 



-, A Dorsal languets short S. oblong a, Herdm. 



(Dorsal languets very large 16 



-.n fHoriz. membr. of branch, sac wide, S. enormis, Herdm. 



{Horizontal membranes narrow ... S. australis, n. sp. 



-j f, (Thorax and abdomen of much the same size ... 17 

 | Abdomen much longer than thorax 18 



-> 7 /Two rows of stigmata in branch, sac, C '.pumilio* M.Edw. 

 [At least six rows of stigmata 19 



-j of Six to eight rows of stigmata G. nana,\ Lah. 



(Twelve to sixteen rows of stigmata 20 



("With yellow or brown lines of pigment on the 



20 thorax C. lepadiformis ,t O.F.M 



(White pigment lines on thorax, C. rissoana, M.Edw. 



Only three or four rows of stigmata in branchial 



18- sac G. producta, M.Edw. 



About a dozen rows of stigmata, C.savigniana, M.Edw. 



(With about four rows of stigmata (Perophora) ... 21 

 10 - With more than a dozen rows of stigmata 



(Perophoropsis) P. herdmani, Lah. 



(Ascidiozooids on distinct jointed pedicels, 

 oil some adhering sand on test, P. hutchinsoni, Macd. 

 J Ascidiozooids not on distinct pedicels, no jointing 

 1 present, no adhering sand 22 



I Body colourless, 40 tentacles of 3 sizes, only 

 papilliform connecting ducts... P. listeri, Wiegm. 

 Body greenish, 20 tentacles of 2 sizes, papilliform 

 connecting ducts with rudimentary internal 

 longitudinal bars P. viridis, Verr . 



(? = P. banyulensis, Lah.) 



This family is of very great interest phylogenetically, 

 (1) because Clavelina comes nearer than any other known 

 form to what we have good grounds for believing the 

 common ancestors of all the simple and compound Ascid- 



*Possibly the young of 0. lepadiformis or some other species. 

 tWith several varieties, 



