18/8.] MR. G. F. AN GAS ON NEW BIVALVE SHELLS. 859 



Fig. 6. Syntomis albifrons, n. sp., p. 845. 



7. Dreata taooensis, n. sp., p. 848. 



8. Syntomis berinda, n. sp., p. 845. 



9. Potera marginata, n. sp., p. 852. 



10. Pitasila moolaica $ , n. sp., p. 847. 



11. Hyperythra angulifascia, n. sp., p. 851. 



12. Omisa sckistacea c?, n. sp., p. 851. 



8. Descriptions of six Species of Bivalve Shells in the Collec- 

 tion of Mr. Sylvanus Hanley, F.L.S., and of a Helix 

 from the Solomon Islands. By George French Angas, 

 C.M.Z.S., F.L.S., &c. 



[Received September 19, 1878.] 

 (Plate LIV.) 



Semele hanleyi, n. sp. (Plate LTV. fig. 1.) 



Shell transversely ovate, subequilateral, solid, cream-coloured, 

 tinged with violet below the umbones, with narrow irregular de- 

 scending white rays towards the base, with several zigzag purplish 

 markings near the centre of the valves; sculptured all over with 

 narrow prominent close-set, somewhat flattened, transverse ridges, 

 which become rather sharp and irregular posteriorly and erectly 

 scabrous at the margin, whilst radiating from the umbones close to 

 the anterior dorsal margin are six close-set ribs, upon which the 

 transverse ridges become nodulous at the points of intersection ; um- 

 bones prominent, sharp, approximate ; posterior dorsal margin nearly 

 straight, anterior one very slightly incurved, ventral margin acute ; 

 dorsal area stained with deep purple ; valves slightly gaping and 

 flexuous posteriorly ; interior of the valves yellow in the middle, 

 stained with rays of violet and rose-colour. 



Long. 11, alt. 8, lat. 4 lines. 



Hab. Japanese seas {Belcher). Collection of Hanley. 



A very charming shell ; the sculpture of the anterior portion re- 

 minding one of certain species of Psammobia. 



Semele aphrodite, n. sp. (Plate LIV. fig. 2.) 



Shell orbicular, nearly equilateral, rather thin, white, with the 

 posterior half of the umbones tipped with rose-colour, from which 

 descend four or five irregular bundles of more or less narrow, faint 

 pink rays, which become a little deeper in colour at the lines of 

 growth and near the base ; concentrically sculptured with narrow, 

 thread-like, somewhat distant lamella?, the spaces between which are 

 crossed with exceedingly fine, close-set, regular hair-like*descending 

 striaj ; umbones rather tumid, sharp, approximate ; dorsal margin 

 posteriorly very slightly arched, anteriorly a little incurved ; dorsal 

 area freckled with a few reddish spots ; ventral margin strongly 

 arcuate. 



Long. 7, alt. 6, lat. 3 lines. 



