S L E N ambiguLis. 

 Ambigifous Solcn. 



Generic Character. 



Testa bivalvis, a-quivalvis, transversissime elongcUa, utroque latere hians. Denta 



ciirdinales parvi, Jragiles, numero variubUes, rwo divarkati. Ligamoi- 



tum externum; unmal ad extremitatem anteriorem pede siibcylindraceo ; 



ad poUcriorem siphone brevi duos altei'os conjunctos conflnente Lamarck. 



Typus Genericus Solen Vagina Pennant. 



Shell bivalve, equivalve, very transversely elongated, open at both ends. 

 Cardinal teeth small, fragile, variable in number, and rarely divari- 

 cated. Ligament external. Animal with a sub-cylindrical foot at 

 the anterior end, and at the other a short tube containing two others 

 united together. Lamarck. 



Generic Type Sokn Vagina Pennant. 



Specific Character. 

 S. testa lineari, crassd, recta, pallida, obscure radiata ; cardinibus uuidentatis, 

 margine anteriore sub-approximantibus. 



Shell linear, strong, straight, pale, obscurely radiated. Cardinal teeth one 



in each valve, placed near the anterior extremity. 

 Solen ambiguus. Lam. Si/st. vol. iii. p. 452. no. 7. 



Under the genus Solen (vulgarly called Razors or Pods) are 

 comprehended a variety of shells having the common character 

 of both extremities open or gaping when the valves are together, 

 3"et differing materially in their form, teeth, and general appear- 

 ance : some are long, slender and straight ; others more or less 

 curved; a few short and oval, or with one end only lengthened. 

 Modern writers have, however, retained nearly all these in the 

 genus as left by Linnaeus ; and this method for the present is 

 more desirable than that of creating a multiplicity of genera. 

 Dr. Turton, in his very useful Conchological Dictionary, enume- 

 rates thirteen species as found on the British coast, including 

 the Solen Novacula of Montagu, wiiich the Doctor suspects is 

 not truly a species. The original specimens which Montagu 

 described I have carefully inspected at the British Museum, and 

 have no doubt in iny own mind they are in reality no other than 

 iS. Siliqua with one of the cardinal teeth broken off'; a circum- 

 stance which, from their fragility, frequently hapj)ens, e\cn in 

 opening the recent shell. 



Solen ambiguus was first described by Lamarck, who says it 

 is from North America. Two or three specimenr^ arc in my pos- 

 session ; but it is a rare species, much thicker, and with larger 

 teeth than any other; the epidermis is pale-brown, and in some 

 parts obliquely lincated. 

 ri. 55. 



