IMPEEFECTLT-KlSrOWN OSTEACODA. 197 



straight in the middle and sloping steeply toward each extremity, ventral straight, 

 with a slight median siuuation: seen from above (fig. 81) ovate, twice and a half as 

 long as broad, acuminate in front, rounded behind, widest in the middle; left valve 

 overlapping the right at both extremities. Surface of the shell smooth, whitish ; 

 anterior and posterior margins fringed with short hairs. Length 2 mm. The two 

 principal ungues of the second maxillar segment laterally spined (fig 3:^). Branchial 

 plate of the maxillipeds (fig. 33) bearing five or six plumose setae ; last joint of the 

 second foot (fig. 34) curved, with two small, but unequal hook-like apical claws, in 

 front of which is a small adpresscd marginal s|>ine, one long apical seta and another of 

 equal length arising from the middle of the joint ; caudal rami with two slightly 

 curved, pectinate, apical claws and two shorter setae (fig. 3-5). 

 Hah. Biskra, North Africa ( Dr. Meinert). Females only. 



Family BAUiDlID.E Brady & Norman. 



Genus Baiedia M'Coy. 



Bairdia LOXGiSETOSA, sp. uov. (Plate XXV, figs. 8, 9.) 



Shell, seen from the side, elongated, subrhomboidal, height equal to more than half 

 the length (fig. 8) ; anterior extremity broad, obliquely subtruncate, rounded off above 

 and below, posterior produced to an acute submedian point ; dorsal margin boldly 

 arcuate, highest in the middle, thence sloping with a steep curve backward, more 

 gently and with a distinct sinuation to the front; ventral margin nearly straight, 

 rounded off in front, sloping upwards behind ; the right valve is overlapped by the left 

 everywhere, except at the upper part of the anterior extremity, and is much narrower 

 and more sinuous in outline, its anterior margin slightly crenulated below, ventral 

 margin armed posteriorly with a series of eight sharp backward-pointing spines ; 

 margins of the right valve devoid of spines : seen from above (fig. 9) the outline is 

 regularly ovate, widest in the middle, acuminate behind, but wider in front, about 

 twice as long as broad. Surface of the shell beset with hairs of moderate length, and, 

 more especially toward the extremities, with extremely long and coarse hairs, some of 

 them reaching one-third the length of the valves. Colour pale brown, semitransparent. 

 Length IT mm. 



Hah. St. Thomas, West Indies. Four specimens. 



Among known species, Bairdia hirsuta Brady is the one which bears most resemblance 

 to the present, but the likeness is not remarkably close, except as to the setose clothing 

 of the shell. B. hirsuta was taken by the 'Challenger' Expedition in o3°-o8° South 

 latitude in the Pacific at depths of from 1375-1825 fathoms. Both B. hirsuta and 

 B. villosa are without marginal serrations or spines. 



2g2 



