231 



Remarks. The present species is nearly allied to C. subcircinatum, but 

 easily distinguished by the greatly projecting caudiform prominene of the shell 

 behind, giving it a quite particular appearance. The shell differs moreover 

 conspicuously in its sculpture, as also in the remarkably blunt anterior extre- 

 mity, as seen dorsally. 



Occurrence. I have only met with this species at the Lofoten islands, 

 where a few female specimens were taken, many years ago, from the con- 

 siderable depth of 120 fathoms. Norman has recorded the species also from 

 great deeps of the Hardanger Fjord. 



Distribution, Not yet observed out of Norway. 



125. Cytheropteron inflatum, Brady. 



(PI. CVI, fig. 2). 

 Cytheropteron inflatum, Brady, Ann. M.ig. Nat. Hist., ser. IV, Vol. II, p. 33, figs. 8 10. 



Specific Characters. Female. Shell moderately tumid, seen laterally, oval 

 subtrigonal in shape, greatest height in the middle and about equal to 3 /s of 

 the length, dorsal margin very strongly, almost gibbuusly arched in the middle 

 and sloping steeply, with a slight concavity, to each extremity, ventral margin 

 slightly sinuated and curving gently upwards behind, anterior extremity some- 

 what obliquely rounded, posterior obtusely produced et the end; seen dorsally, 

 regularly fusiform in outline, with the greatest width in the middle and about 

 equal to the height, side-edges quite evenly curved, both extremities gradually 

 contracted and nearly equal. Valves rather thin, with the surface smooth' 

 only marked with slight scattered pits; alseform expansions simple rounded off. 

 Limbs of a structure very similar to that in C. subcircinatum. 



Colour of shell whitish semipellusid. 



Length of adult female 0.55 mm. 



Male unknown. 



Remarks. The above described species agrees with the 2 preceding ones 

 in the quite simple rounded alseform expansions of the valves, but is easily 

 distinguished from either of them by the general shape of the shell. The 

 specific name is somewhat unappropriate, as the shell in reality is less tumid 

 than in most of the other species. 



Occurrence. A single female specimen only of this form has as yet come 

 under my notice. It was taken at Korshavn, south coast of Norway from a 

 depth of about 30 fathoms, muddy sand. 



Distribution. British Isles. 



