418 



NEW GENUS AND SOME NEW SPECIES 



9. U. rectus, 



Lam.* 



10. U. torsusf, Rafinesque. 



11. U. mytiloides, Rafin. 



« 



12. U. metanever, Rafin. 



13. U. scalenius, Rafin. 



14. U. cornutus, Bar.} 



i 



f prrelongus, 

 J nasuta, 



) purpurata 1 

 [_ recta, 



undatus, 



<f nodosus, 



\ rugosus (flat), 



Bar. 

 Lam. 

 Lam. 

 Valen. 



Bar. 



Bar. 

 Bar. 



riety of crassus. At the same time he mentioned that its discoverer, that excellent 

 naturalist Mr Le Sueur, suspected it to be a new species, and proposed, should 

 this prove to be the case, to call it " plicata." We are, therefore, bound to 

 adopt his name on the claim of priority ; and a more descriptive one could not 

 be given to it. 



* When Dr Hildreth described the " prcelongus," it is evident he believed it to 

 be prtelongus of Barnes, for he uses Barnes's name without stating it to differ from 

 his, although the descriptions are not exactly the same. Barnes says, " Naker, 

 purple of different shades," and " deep and splendid purple." (See Barnes's Re- 

 clamation.) Hildreth says, "Naker, white, and tinged with spots of green." 



The specimen of " recta" described by Lamarck, was " white," according to 

 his description. I have seen very many specimens of this species, some of which 

 are tinted with light purple or salmon about the cavity of the beaks and cardinal 

 tooth ; they are generally, however, of a pure white. The explanation of these 

 contradictory characters is this : The specimen in the collection of the New York 

 Lyceum, and the same is said of one in Dr Mitchill's collection, both brought from 

 the upper lakes, is unusually full of colour, having almost the whole of the nacre of 

 a rose or delicate purple. It has more colour than any specimen I have seen. 



t M. Rafinesque is entitled to a preference in this beautiful and extraordinary 

 species, possessing the most elevated recurved beaks of the whole genus. It was 

 generally known among us by the name of U. orbicularis, but not described. The 

 variety, not emarginate, can not be made a species, as the two pass into each other. 

 Dr Hildreth has recently described a shell, which I believe to be the torsus, in Sil- 

 liman's Journal under the name of U. orbiculatus. He says, " This shell is a va- 

 riety of the crassus." Whose crassus ? Mr Say's, as mentioned before, is a pon- 

 derous cariosus ; Mr Barnes's, a peruvianus ; and, if a variety of crassus, why 

 call it orbiculatus ? 



\ This species is among the most interesting of the genus. It presents a much 

 greater variety than any other, and might be called a real proteus. The true 



