REPORT ON THE OSTRACODA. 103 



iu the middle ; seen from above, the outline is narrow and subhastate, with rounded 

 angles, greatest width situated behind the middle, and somewhat less than half 

 the length ; from the widest point the sides converge gradually towards the front, but 

 with an abrupt curve backwards, each extremity forming a broad truncated prominence ; 

 the margins are throughout profusely and irregularly dentated ; end view ovate, tumid, 

 with very convex sides, and strongly-keeled broad base. The surface of the shell 

 is covered thickly with nodular elevations, and the extremities are produced into 

 flanges which are marked with transverse hair-like lines. Length, 1-3 3d of an inch 

 (•77 mm.). 



Dredged north of Tristan d'Acunha in lat. 32° 24' S., long. 13° 5' W., 1425 

 fathoms. 



[PI. XXIII. fig. 1, a-d. a Shell seen from left side, b from above, c from below, 

 d from front. Magnified 50 diameters.] 



72. Cythere scabrocimeata, n. sp. (PI. XVII. fig. 5, a-f, and PI. XXIII. fig. 2, a-c). 



Very like Cythere dorsoserrata, but more tumid, more nearly ovate in its dorsal 

 aspect, and having all its margins more uneven ; seen from the side, the shape of the 

 female shell is that of a long triangle with the apex behind, all the margins, but especially 

 the dorsal, denticulated or jagged, highest in front, the dorsal and ventral mai'gins gently 

 curved and converging equally to the pointed posterior extremity ; seen from above, the 

 outhne is ovate, twice as long as broad, and widest near the middle, extremities broad 

 and rounded off", lateral margins curved and converging rather more abruptly behind than 

 in front. Shell-surface rough, with prominent nodules and scattered ill-defined lidges. 

 Length, l-33d of an inch (77 mm.). The shell of the male is a good deal narrower and 

 longer. 



Dredged off" East Moncoeur Island, Bass' Straits, in 38 to 40 fathoms (Station 162) ; in 

 the Inland Sea, Japan, lat. 34° 20' N., long. 133° 35' E., 15 fathoms (Station 2336) ; and 

 in Wellington Harbour, New Zealand. 



The lateral aspect of the specimens referred to Cythere scahrocuneata is so closely 

 similar to that of Cythere dorsoserrata as to lead to the suspicion that the two forms may 

 be specifically identical. And still more doubt may be entertained as to the proper 

 position of the valves figured in PL XXIII. fig. 2, a-c, which I consider for the present 

 as a variety of Cythere scahrocuneata. This is one of the numerous cases in which 

 further observation on a more extensive series of specimens is required before a satisfactory 

 decision can be arrived at. 



[PL XVII. fig. 5, a-f. a Shell of female seen from left side, b from above, c from below, 

 d from front, e male seen from left side, f from above ; PL XXIII. fio-. 2, a-c, a, 

 left valve (variety) from side, b left valve (variety) from side, c the same from above. 

 All magnified 50 diameters.] 



