234 Mr. E. A. Smith on the Genus Pythiiia. 



18. " Pythina compaxita^Go\x\(\.'''' (Tiyon). 



Kellia compacta, Gould, Proc. Boston Soc. Nat. Hist. 18G1, vol. viii. 



p. 33; Otia Conch, p. 173. 

 Pythina cotnpacta, Tryon, Proc. Acad. Nat. Sci. Philad. 1872, p. 232. 



Hah. ? 



Respecting tlie hinge of this species Gould writes : — " Val- 

 vules alterge dentibus duobus niagnis, divergentibus, cquali- 

 bus ; alteree n^avginibus dentibus simulantibus, elongatis ; 

 fossa Hgamentali arapla." " Its hinge is like that of Pi/thina, 

 Hinds. A knowledge of the animal can alone remove it 

 definitely from the old genus KelUa.''^ 



From this two things are evident : firstly, that this species 

 belongs to Tellimya^ and, secondly, that Gould did not know 

 Pytliina nor the exact dentition of Kellia. 



Tryon was probably induced to place this species in 

 Pythina through Gould's statement respecting its similarity 

 of dentition. 



19. Pythina rugifera^ Carpenter. 

 Pythina rugifera, Carpenter, Proc. Acad. Nat. Sci. Philad. lS6o, p. 57. 



Hah. Puget Sound, west coast of North America. 



The hinge of this species is thus described by Carpenter: — 

 " Dente cardinali uno minore, clavicula antica laterali incon- 

 spicua ; laterali postico nuUo." This description shows that 

 the shell in question is quite distinct from Pythina { = Kellia) . 

 Without seeing a specimen it is impossible to state its true 

 position ; but temporarily I suggest its location in Montacata, 

 from the fact of there being no posterior teeth. 



Conclusions. 



From a perusal of the preceding observations it will be 

 seen — 



(1) That the so-called genus Pytliina differs from Kellia 



only in having the surface ornamented with divari- 

 cating plicffi, a feature, in my judgment, only of 

 specific value. 



(2) That it is restricted to one species, namely P. 

 Deshayesiana of Hinds. 



(o) That the eighteen other species which have been located 

 in Pythina should, accurdimj to their conchological 

 charactcrti, be thus classilicd : — 



