1902.] NATURAL SCIENCES OF PHILADELPHIA. 513 



BY ADA SPRINCiEK. 



In the Plebloceae beds of the Arroyo Pecos at La^ V^gas, K 

 M are found many fluviatile and terrestnal shells, melnd.ng the 

 ^LZphysa. Li,La. Planorbu. Ancyln., Pi^idum, Sph.raun, 



Pupoides and Vallonia. 



None of the species, so far as known, are extinct bnl some 

 u]l Sphoerium l,m« Sterki MS.) do not appear to ex,s any 

 longer in the vicinity; while others exhibit vanelal character, vvh ch 

 'Ifto distinguish ihem ,nore or less from l^eir liv,ng rep^sen^^ 

 tives The genus Phym is represented m those beds by very 

 n™ erons indfviduals, differing considerably in form but ap^r- 

 en In pertaining to a single species. This ^P^c- >>- >«*" 

 dentified at the National Museum as Pkysa hu,»ero.aGoM, and 

 ther is no reason to doubt the identity. The ongmal descr,pt»n 

 Tp lnmero>a, kindly copied by Mr. C. T. Simpson, .s as follows; 

 . ltrs„b;homboLa, solidula, polita, albida sptra acuta; 

 anfrao 5, tabulatis; apertura 4 ad | long. test=e adeqttans, post ce 

 itnL;; labro expanse; colmnella vix plicala, callosa, fere 



'"■■'T'"' 1 ,1 ' ™,11 • ht a ,„11. Found by Thmnas H. 

 wl^rn'dVwTBlakirin t"he' Colorado desert and at Pecos 



""fxhe broadly tabulated whorls, and the acute, elevated spire 

 and foldtes pillar clearly distinguish this spec.es. It « '■ke 

 P. ialuMa Gould, and the variety figured by Halden an ^ P. » 

 miliaria ffi" 7), which he regards as a monstrosity; the deep 



"^ran'd the si'mple columella dis.ingidsh it f™™*- species^ 



The species was first published in B-oc. Bod. Soc. Aof. ««'. , 

 VoT V ri26, February, 185.5. The National Mu.sei,m ,x>s^s 

 ^H from ColoiJ, lake, received origUially ^o,„ B^ke 



(Lea Collection), which are supposed to be cotyi«s. Mi. Snnp*n 



33 



