EEPORT ON THE OSTRACODA. 61 



22. Bairdia acanthigera, G. S. Brady (PL IX. fig. 4, a-c). 



Bcdrdia acanthigera, Brady, Trans. Lin. Soc, 1868, vol. xxvi. p. 390, pi. xxvii. figs. 18-21. 



Carapace oblong, tumid ; seen from the side, subreniform, twice as long as broad j 

 anterior extremity rounded (usually dentate), posterior narrowed, and fringed with a few 

 small teeth ; dorsal margin gently arched, ventral slightly sinuated in the middle ; seen 

 from above, ovate, twice as long as broad, with nearly parallel sides, and abruptly 

 tapered, rather obtuse extremities ; end view broad, subovate, widest below the middle, 

 height and width nearly equal. Shell-surface nearly smooth, marked with numerous small 

 circular punctures, and towards the hinder extremity slightly hirsute. Length, l-30th of 

 an inch ('85 mm.). 



This species occurred in a dredging from a depth of 1070 to 1150 fathoms off St Vin- 

 cent, Cape Verde, muddy bottom (Stations 93 and 94). Except from a few stations in 

 the English Channel, whence the type specimens were derived, I do not know of the 

 occurrence of Bairdia acanthigera elsewhere. The .specimen from which the artist 

 has drawn his figures appears to have been without the usual row of teeth on the anterior 

 margin ; these teeth, however, constantly exist on adult specimens as far as my observa- 

 tion goes. 



[PL IX. fig. 4, a-c. a Carapace seen from left side, h from below, c from front. 

 Magnified 40 diameters.] 



Family 11. Cytheeidje. 



Shell mostly hard and compact, calcareous ; surface generally more or less rough and 

 uneven, occasionally quite smooth. Hinge margins mostly toothed; antenna not 

 adapted for swimming, the anterior composed of from five to seven joints, and armed 

 with various setse or spines ; posterior four-or five-jointed, last joint the smallest, and 

 armed with one to three curved claws, second joint destitute of the brush of setse, which 

 mostly exists in the Cypridae; first joint giving origin, at its apex, to a long biarticulate 

 tubular seta, which extends downwards in front of the antenna, about as far as the last 

 joint, and is connected above by an efferent tube, with a gland situated in the body of the 

 animal. Mandible very similar to that of the Cypridse. One pair of jaws, composed of 

 four segments, wdth a branchial plate. Three pairs of feet dii-ected forwards, very much 

 alike in shape, but increasing in length from before backwards ; all of them adapted for 

 creeping, and terminating in a single strong curved claw. The fii'st foot corresponds with 

 the palp of the second maxiUa in the Cypridse, the cutting segments being represented 

 by two small setiferous appendages, arising from a common base. Postabdomen 

 rudimentary, and almost obsolete, forming two small lobes or setae. Eyes mostly 

 separate, sometimes confluent, more rarely altogether wanting. Ovaries and testes not 



