378 MR. G. S. BRADY ON NEW OR IMPERFECTLY 
Var. rupris. (Pl. LX. fig. 6, a—c.) 
More rounded in outline; the tubercles and ridges of the carapace obsolete. Surface 
undulated, marked with large oval pittings, chiefly on the anterior half of the valves. 
Posterior extremity bearing a few small teeth. 
Length 35 in. (386 mm.). 
Hab. Atlantic Ocean (223 fathoms, Commander Dayman’s soundings). 
The form which I have named rudis appears in all important characters to agree 
with the present species (C. lactea). Probably the paucity and indistinctness of its 
surface-markings may be attributed to the combined effects of old age and peculiarity of 
habitat. 
14. Cyrnere pumita, n.sp. (PI. LX. fig. 7, a—d.) 
Carapace compressed, oblong, quadrilateral. Anterior extremity broad, obliquely 
rounded; posterior narrow, flattened, produced below. Ventral and dorsal margins 
nearly straight. Seen from below, the outline of the carapace is compressed, oblong, 
with parallel sides and truncated pyramidal extremities. Surface covered with strong, 
irregularly disposed ribs, marking out about four large and several smaller fosse, and 
dividing somewhat dichotomously towards the anterior margin. 
Length 35 in. (‘54 mm. ). 
Hab. Australia. One specimen. 
15. CyrHere propucra, n.sp. (Pl. LIX. fig. 11, a-d.) 
Carapace oblong, quadrilateral, convex ; extremities equal. Anterior margin rounded, 
forming a flattened border, which is much produced at the ventral angle. Inferior half 
of the posterior border produced backwards into an irregularly toothed process. Dorsal 
and ventral margins parallel, nearly straight. Dorsal aspect ovate. Surface of the valves 
marked with quadrangular pits arranged in longitudinal rows, and becoming obsolete 
towards the dorsal margin. 
Length 3}; in. (‘74 mm.). 
Hab. Honduras (shallow water in calcareous sand). 
16. CyrHerE pavonta, n.sp. (PI. LXI. fig. 2, a-d.) 
Carapace oblong, compressed, rather gibbous in the centre, ending posteriorly in an 
oblique ridge, which forms three crescentiform excavations near the lower posterior 
angle. The anterior border is broad and well rounded ; the posterior narrow, oblique, 
and emarginate. Dorsal margin nearly straight ; ventral slightly sinuated.. The ventral 
profile is compressed, lanceolate, showing on the posterior half of each valve three large 
and deep circular fossee, which are surrounded by elevated borders. These, seen in 
profile, form the crescentic ridges which are visible on the lateral aspect. Valves 
