40 HELICEA. 



SUCCINEA HAYDENI. 



PLATE LXXIX. FIGURE 1. 



Testa elongato-ovalis, tenuis, pellucida, succinea ; spira parva, acuta ; 

 anfr. 3 convex!, ultimus rugis levibus incrementalibus et sulcis crassis 

 spiralibus, interruptis, inequaliter notatus ; sutura mediocris ; columella 

 callo levi induta, apicem interiorera a basi testae monstrans ; apertura 

 obliqua, ovalis, 5-7 long, testae aequans, ad basin expansior. 



SYNONYMS AND REFERENCES. 



Succinea Haydeni W. G. BINNEY, Proc. Acad. Nat. Sc. of Phila. x. p. 114. May, 



1858. Notes, p. 15. 



DESCRIPTION. 



Animal of an uniform amber color, judging from the 

 specimens preserved in spirits in the collection of the 

 Smithsonian Institute. 



Shell elongate-oval, thin, shining, amber-colored ; spire 

 short, acute ; whorls three, convex, the last marked with 

 the wrinkles of growth, and irregular, heavy, spiral fur- 

 rows ; suture moderate ; columella covered lightly with 

 callus, and allowing all the interior whorls to be seen 

 from below to the apex ; aperture oblique, oval, 5-7ths the 

 length of the shell, the lower portion of its margin con- 

 siderably expanded. 



Length 21 ; diameter 9 millimetres. 



Geographical Distribution. Found in considerable num- 

 bers by Dr. F. V. Hayden, the Geologist of the Yellow- 

 stone Exploring Expedition, in Nebraska, between the 

 rivers Loup Fork and L'eau qui court. 



Var. Minor. Length 15 mill. Found by Mr. Robert 

 Kennicott near the Red River of the North. 



Remarks. This is the largest known American Suc- 

 cinea. 



Mr. Say describes S. ovalis as showing the interior apex 

 from the base of the shell ; in other respects his descrip- 

 tion does not apply to this shell. Its aperture is nearer 

 that of S. ovalis Gould non Say, but the peristome is 



