48 



In some specimens there are faint indications of a mesial sinus on the 

 ventral valve, but in general the form is smoothly lenticular without either 

 fold or sinus. In small individuals the apical angle is often much less 

 than that above given, the most acute being 107?. 



A. SOLITARIA, n. sp. — Shell transversely ovate, lenticular ; front mar- 

 gin with a small space in the middle straight or concave. Ventral valve 

 moderately convex ; umbones and beak small, the latter closely incurved ; 

 a mesial sulcus, sub-angular in the bottom, commences on the umbo and 

 becomes gradually wider and deeper to the front margin where it is about 

 one-fourth the whole width of the shell. Dorsal valve gently convex with 

 a faint double mesial fold. Surface with obscure concentric striae. Length 



5 lines ; width 6 lines. South-west Point ; Div. 4, A. G. J. Richardson. 

 Only one specimen collected. 



C. Myrtea, B., op. cit., p. 165. — South-Avest Point; Div. 4, A. G. 

 Genus Spirifera, Sowerby. 



S. PLICATELLA, Linn. — South-west Point, and the Jumpers ; Div. 4, 



A. G. 



Genus Leptoc(ELIA, Hall. 



L. HEMISPHERICA, Sowcrby. — South-west Point, the Jumpers, and East 

 Pobit ; Divs. 3, 4. 



LAMELLIBRANCHIATA. 



Genus Modiolopsis, Hall. 



M. STRIATA, n. sp. — Shell moderately convex ; anterior extremity 

 short, rounded and somewhat compressed ; ventral margin straight or 

 slightly concave for a short space in the anterior half ; posterior extremity 

 broadly rounded in the ventral half ; apparently sub-angular at the mid- 

 height, obliquely and convexly truncated above. The beaks are small, 

 closely incurved, about one-sixth the whole length from the anterior ex- 

 tremity. The umbones moderate ; greatest gibbosity a little behind the 

 mid-length and above the mid-height. The posterior point of the dorsum 

 is imperfect, in all the specimens observed, but judging from the course of 

 the strise it appears to be gently rounded from the end of the hinge line, 

 downwards. This point is also somewhat compressed. Surface with fine 

 but very distinct concentric strise from eight to ten in one line. Length 

 14 lines ; greatest width, at about one-fourth the length from the posterior 

 extremity 11 lines ; width at the umbones 9 lines. Depth of both valves 



6 lines. Another specimen has a length of 15 lines ; width 12 lines ; 

 depth of both valves 7 lines. This specimen has a more widely ventri- 

 cose aspect than the former, but seems to be certainly of the same species. 



