28 G. O. Sars. 



yalve, however, slightly overlapping the left along the ante- 

 rior extremity and the lower part of the posterior, free edge 

 of left valve, as in the 2 preceding species, minutely tuber- 

 cular; surface smooth and finely hairy at both extremities. 

 Eye of quite unusual size and highly refractive, occurring 

 more in front than in the 2 preceding species. Caudal rami 

 comparatively narrower than in H. ovata, otherwise of a 

 very similar structure. 



Colour. — Shell semipellucid, of a fine straw-colour, 

 and exhibiting near the dorsal face 2 irregular, somewhat 

 band-like patches of a light chest-nut hue, centre of shell 

 bluish green on account of the translucent anterior dilat- 

 ation of the intestine; coecal appendage of same colour. 



Length of shell 086 ^m^ height 0-54 "^i"^ width 0-48 ™n\ 



Remarks. — This species is closely allied to H. ovata, 

 but of smaller size, and having the shell comparatively 

 shorter and more regularly oval in form. It is also easily 

 distinguished by the colouring of the shell and by the un- 

 usually large size of the eye, a character which has given 

 rise to the specific name here proposed. 



Occurrence. — Some specimens of this form were found 

 in the same aquaria in which the 2 preceding species devel- 

 oped. It did not, how^ever, occur in the sample taken by 

 Mr. Iversen. 



Gen. Leptoeypris, G. O. Sars, n. 

 Generic Characters. — Shell very thin and highly 

 compressed, oblong in form, with the valves subequal ; sur- 

 face closely striated longitudinally, inner duplicatures very 

 narrow. Eye comparatively small. Natatory setæ of inferior 



