20 



Gr. O. SARS. 



[No. 8. 



in its posterior part (see fig. 2), forming, as it were, a triangu- 

 lar shield, arching over the bases of the antennæ; nioreover, it 

 is drawn out on either side to a sharp and freely projecting 

 spiniform point, jutting alraost at right angles to the axis of 

 the body. 



The carapace, as viewed from the side (see fig. 1), exhibits 

 a broadly oval form, with the dorsal margin more or less arched 

 — according to the number of eggs, or embryos, in the matrix — 

 and the free edges of the valves forming an even curve through- 

 out. At the junction between the two posteriorly, projects the 

 very strong spine of the carapace, pointing invariably somewhat 

 obliquely upward, even should the matrix be greatly distended 

 with eggs, or embryos. Generally, it equals in length the whole 

 of the carapace, and is, as usual, armed with 4 rows of 

 small appressed denticles, the two upper continuing along the 

 dorsal edge of the carapace well-nigh as far as the dorsal 

 impression. The free edges of the valves are in the most 

 anterior part quite smooth, but, for the rest, armed with a series 

 of from 16 to 20 unusually slender and distant denticles, largest 

 in the middle and diminishing a trifle in length both forwards 

 and backwards. 



As to the sculpture of the snell, it appears very faint and 

 difficult to detect, but would seenl to resemble that in other 

 Daphniæ, two systems of delicate striæ crossing each other at 

 equal intervals and thus forming a very close and regular net- 

 work. The shell-gland is easy to examine and of the usual 

 structure, constituting an S-shaped assemblage of canals in the 

 anterior part of the valves. 



The eye occurs comparatively large and provided with numer- 

 ous refracting corpuscles, from 8 to 10 of which project at the 

 periphery from the edges of the black pigment. The ocular spot, 

 or ocellus, on the other hand, is exceedingly small, so as to be 

 easily overlooked. 



The antennulæ are, as in other female Daphniæ, very small 

 and quite immobile, though in this species distinctly projecting 

 with their extremities from a small rounded prominence just 



