CLASSIFICATION OF THE TFNICATA. 581 



q /Body on a well-marked peduncle 11 



[Body sessile 12 



{Peduncle slender, meshes with 6 or more stigmata. 

 S. clam, Herdm. (N. Pac.) 

 Peduncle not very slender, meshes with only 2 stigmata. 

 S. gelatinosa, Traust. (Arct.) 



19/Languets present S. hythia, Herdm. (A. Arct.) 



"^ \ Dorsal lamina a plain membrane 13 



-.0 f Test with hair-like prolongations from surface 14 



\Test with no such prolongations 15 



1 - f Black on surface, hairs few and large. 8. solearis, Sav. (Red S.) 

 I Grey, hairs small and felted S. cinerea,Sa\. (Red S.) 



1 r r Dorsal tubercle large and complicated. S. mytUigera, Sav. (Red S.) 



\ Dorsal tubercle not large nor complicated 16 



,p f Very many stigmata in a mesh 17 



\ Meshes not exceedingly elongated 18 



(Body pyriform, apertures with more than 4 lobes. 

 8. grandis, Herdm. (A. Arct.) 

 Body barrel-shaped, apertures, 4-lobed. 

 8. lactca, Herdm. (A. Arct.) 



^r,{ Individuals aggregated 19 



I Individuals not aggregated 20 



r Surface sulcated, of a white colour... 8. plicata, Les. (Oosmop.) ( = & 



19 I Surface not sulcated, of a reddish colour. [ggrosa, Hell.) 



[ 8.aggregata, O.P.M. (N.W.Eur.) 



Stigmata 3 in a mesh 8. convexa, Herdm. (A. Arct.) 



Stigmata more than 3 in a mesh 21 



r Meshes not divided transversely 22 



\ Meshes divided transversely 23 



20 



21 



f,£j / Body broad (dorso-ventrally) 8. scorfea, n. sp. (Austr.) 



""' I Body long (antero-posteriorly) 8. radicosa, 'S-vTAm. (Austr.) 



(Colour pale yellowish grey, siphons violet inside. 

 8. canopus, Sav. (Red S.) 

 Colour red, siphons not violet inside. 8. canopoides, Heller. (Med.) 



For imperfectly known species, see p. 585. 



Sttelopsis, Trausteclt, 1882. 



Body globular or cylindrical, attached, not incrusted with 

 sand. Apertures both 4-lobed. 



Branchial sac with the folds reduced to a single one placed 

 near the dorsal edge of the right side, the other 7 being quite 

 rudimentary. 



Gojiads on the right side only. 



This genus was formed for the reception of the single species 

 Styelopsis grossularia, Van Beneden, common on the north- 

 western shores of Europe. 



