366 MR. G. S. BRADY ON NEW OR IMPERFECTLY 
myself off the Isle of Man, have the posterior extremity remarkably spinous, and are 
likewise beset with strong brown sete, in this respect somewhat resembling B. fusca. 
6. BairpiA crosskEIANa, n. sp. (Pl. LVIL. fig. 10, a—d.) 
Triangular, convex, compressed posteriorly. Left valve large and overlapping the 
right ; broad, obliquely rounded anteriorly, and tapering to an acute, produced pos- 
terior extremity ; highest at anterior third. The anterior border is armed with several 
short, pointed tubercles or spines ; the posterior is acutely pointed, and has a squamous 
lamina, which is continued along the posterior third of the ventral border. Ventral 
margin convex ; the dorsal margin much elevated at its anterior third, from which it 
slopes steeply to the posterior extremity. The right valve is smaller, its dorsal margin 
truncated in the middle; anterior extremity broad, obliquely convex, and denticulate ; 
posterior extremity beaked ; ventral margin slightly sinuated. Viewed from below, the 
carapace is hastate in outline, very acute posteriorly, and broadest at its anterior third. 
Surface of the valves smooth, finely punctate. Lucid spots as in B. subdeltoidea. 
Length 35 in. (1 mm.). 
Hab. Levant (sponge-sand). 
Well characterized by the hastate outline as seen from above, the greatly produced 
tapering hinder extremity, and the spinous anterior border. There are, however, some 
forms of Bairdia subdeltoidea, from Australia, which closely approach it; and it isa 
matter of the greatest difficulty to determine the real limits of the various species. 
My impression is, that the most correct and natural arrangement would be to retain 
the present B. subdeltoidea as the typical form of the species, classing under it, as mere 
local varieties, B. amygdaloides, B. crosskeiana, and possibly some of the fossil species 
described by Continental authors. 
Genus Cyrueripeis, Jones (subgenus). 
Animal a Cythere. Carapace oblong-oval, reniform, or subtriangular. ‘‘ Hinge-mar- 
gin simple, except that, the central portion of the dorsal margin of the left valve being 
somewhat incurved under that of the right valve, the anterior and posterior angles of 
the dorsal margin of the left valve remain somewhat projecting, and present internal 
shallow furrows for the reception of the corresponding angles of the opposite valve: 
ventral margin partially incurved.”’ 
1. CyrHERIDEIs DEcorA, n. sp. (PI. LVII. fig. 13, a—c.) 
Carapace elongated, triangular, slightly narrowed posteriorly, and highest in the 
middle. Both extremities rounded, the posterior somewhat produced. The dorsal 
margin is arched and rather flattened; ventral margin slightly arcuate. Seen from 
