165 



both ends, sometimes having the outer surface crossed obliquely 

 tvith stria, which end abruptly on an anterior angle ; hinge 

 composed of two divergent central teeth in each valve ; liga- 

 ment external, supported on a moderately thickened fulcrum. 



Before the animal of Solecurtus had been observed, conchologists were 

 pretty well agreed on the propriety of separating the richly coloured, deli- 

 cately rayed, oblong-ovate Solens, some of them inhabiting brackish waters, 

 from the narrowly attenuated Solens proper. Even a further subdivision 

 of Solecurti has been made into the genera Pharus [Ceratisolen, Forbes), 

 P/iarella, Cultellus, Siliqua, and Novaculina ; but in all these the differ- 

 ences of the animal are chiefly modifications of a greater or less extension 

 and separation of the siphons, to which it may be useful to have regard at 

 some future time when more species shall have been discovered, or when, 

 according to Mr. Darwin's theory, they will have become more numerous 

 by intermarriage. In the Solens or Razors proper the animal has a pecu- 

 liarly elongated cylindrical form, and the siphons are short and united. 



The Solecurti have for the most part a beautifully painted shell, rayed 

 often in the most delicate manner with violet or rose, and some are marked 

 with waved lines crossing the shell obliquely over the lines of growth and 

 ending in a singularly abrupt manner on an anterior angle radiating 

 linearly from the umbo. It is in the S. strigillatus, a native of the Medi- 

 terranean, in which this peculiarity is most conspicuous, but it also ap- 

 pears in the British S. candidus of the same type. Professor E. Forbes 

 remarks of both these species that he has seen them dilate their siphons to 

 such a degree as to break them up into fragments. 



The fresh-water species, separated under the head of Novaculina, have 

 more elongated shells, of more sombre hue, and inhabit chiefly the mouths 

 of rivers in India and China. They abound also in some of the American 

 rivers. The more delicate rayed forms, such as S. radiatus and violaceus, 

 constituting Mublfeldt's genus Siliqua, inhabit the tropical shores of India 

 and China, and the type is also represented in the Arctic seas by a few 

 characteristic species. 



1. acuminatus, Hani. 



2. acutidens, Brod. 



3. albus, Mart. 



4. albidus, Ad. §r Rv. 



5. bidentatus, Sjpeng. 



6. Calif ornianus, Conr. 



7. candidus, Ren. 



Species. 



8. coarctatus, Gmel. 



9. constrictus, Lam. 



10. costatus. Say. 



11. cultellus, Linn. 



12. exaratus, Phil. 



13. Gangeticus, Bens. 



14. gibbus, Spei/t/. 



15. Javanicus, Lam. 



16. legumen, Linn. 



17. maximus, Gmel. 

 13. niedius, Sow. 



19. minimus, Gmel. 



20. Nuttallii, Conr. 



21. olivaceus, Mete. 



