1899.] NATURAL SCIENCES OF PHILADELPHIA. 185 



NEW AND LITTLE-KNOWN SPECIES OF PRISTILOMA, 

 , BY HENRY A. PILSBRY. 



In the handbooks of American land mollusks published by Mr. 

 W. G. Binney, as well as in the more general Manual of Tryon, 

 but two species of the genus Pristiloma are recorded : P. Lansingi 

 and P. Stearnsi, both described by Thomas Bland in 1875. The 

 original figures and descriptions may also be found in Binney' s 

 Manual of American Land Shells (1885), and additional informa- 

 tion, especially as to distribution, is given by the same industrious 

 author in the Supplements to the Fifth Volume of Terrestrial Mol- 

 lusks. To these sources reference is made for the literature of the 

 species. 



A third species, apparently of this genus, was described from 

 Point Barrow, Alaska, by Mr. E. Lehnert, in 1884, under the 

 name Hyalina arctica ; and Mr. E. G. Vanatta has quite recently 

 described a fourth one.^ In adding the fifth species to the genus, 

 I have felt it incumbent on me to redefine and figure Lehnert' s 

 Hyalina arctica, until now unfigured, and not described with 

 sufficient exactness to insure recognition," nor mentioned in the 

 Zoological Record. 



Pristiloma is probably closely allied to Conulus, differing from 

 that genus chiefly, so far as known, in the ribbed or plaited jaw- 

 But it is only in P. Lamingi and P. Stearnsi that this form of jaw 

 has been demonstrated; and the other species herein considered to 

 be congeneric with those mentioned are referred to that genus 

 solely upon the resemblance of the shells. Some of them may 

 prove to be depressed forms of Conulus, as Dall (in Hit.) suggests 

 to me. 

 Pristiloma Taylori n. sp. PI. IX, figs. 6, 7, 8. 



Shell imperforate, discoidal, thin, transparent, corneous, clearly 

 showing the yellow soft parts when these are dried in it ; surface 



^ These Proceedings, p. 120. 



^That this is the case is shown by the fact that it has hitherto been 

 referred to P. Stearnsi as a synonym, though it is much more nearly allied 

 to P. Lansingi. 



