9 
rather broad, with two anterior serrated cardinal teeth in each 
valve, a narrow diverging posterior one, and a rather broad, 
deep cartilage pit between ; lateral teeth narrow and but little 
raised. 
Measurement :—Anterior to posterior, 29; umbones to 
ventral margin, 21}; thickness (valves united), 14 millim. 
Hab. :—Martha Point (South Coast), N}#W., 93 miles; 
depth, 42 fathoms ; bottom, green mud (one specimen only). 
CRASSATELLA ANGULATA, n.sp. (Plate VI., fig. 16). Shell 
transversely oblong, angular behind, rounded in front, whitish, 
covered with a light yellowish brown periostracum, very finely, 
concentrically striated, roughly and irregularly plicated with 
growth lines; posterior side rather concave, with an obtuse 
rounded, somewhat-incurved angle from the umbones to the 
lower extremity. Posterior dorsal margin long, rather straight, 
very slightly sloping, terminating in an obtuse angle ; anterior 
short, sloping ; posterior lateral margin nearly straight, rather 
oblique, anterior rounded, ventral slightly convex. Umbones 
minute, very slightly incurved, posterior cardinal area rather 
short, flattened, rather deep, rather broad in the middle and 
pointed at each end ; anterior lunule rather long, with a narrow 
heart-shaped cartilage orifice. Interior white, smooth, 
minutely crenulated within the margin ; abductor scars raised ; 
pallial line simple.” Hinge as in C. Gilchristi, but with lateral 
teeth shorter: 
Measurement :—Anterior to posterior, 28; umbones to 
ventral margin, 18; thickness (valves united), 13 millim. 
Hab. :—Umhlangakulu River Mouth, N.W. by N., 73 miles ; 
‘depth, 50 fathoms; bottom, sand and shells (one specimen 
only). 

CRASSATELLA AFRICANA, n. sp. (Plate VI., fig. 13). Shell 
‘sub-ovate, compressed, rather thick, with a faint posterior 
angle ; surface concentrically closely lirate, liree raised and 
regular near the umbones, becoming irregular and less distinct 
towards the ventral margin, everywhere decussated by ex- 
tremely fine concentric and radiating strie, covered by a thin 
light brown periostracum. Dorsal margin sloping on both 
sides, posterior long, anterior rather short ; anterior lateral 
margin rounded, posterior convexly truncate ; ventral margin 
convex. Umbones minute, scarcely incurved ; cardinal area 
rather long on each side, depressed, slightly concave, anterior 
narrow, posterior broader. Interior white, smooth, with a 
minutely cremulated margin; abductor scars, pallial line, 
and hinge as in C. Gilchrist. 
