68 PRATICOLELLA-POLYGYRA. 



opening into the penis by a narrow aperture, and containing two 

 strong longitudinal fleshy ridges (pi. 21, fig. 3). Talon coronated 

 (pi. 21, fig. 4). 



Jaw arcuate without median projection, sculptured with numerous 

 (12-14) broad, crowded ribs, denticulating both margins, (pi. 21, 

 fig. 5, P. ampla). 



Radula having the central teeth tricuspid, mesocones with a long 

 reflection, the cutting points projecting beyond the basal-plates, ecto- 

 cones shortly reflected with long cutting points. Laterals similar 

 but lacking entocones. Marginal teeth low, wide, the mesocone and 

 ectocone both bifid (pi. 21, fig. 6, P. griseola). 



Distribution : eastern Mexico and Texas. The species live in 

 open fields and chaparral. 



The most important anatomical features of this group are the 

 simplicity of the female generative system, which is like Polygyra in 

 its' short spermatheca duct, lobed talon and other characters; the 

 male system being also like Polygyra except that the retractor has a 

 triple insertion, and the penis has a large appendix. Jaw as in 

 Polygyra, section Stenotrema ; teeth of radula as in Polygyra. 

 External features also like Polygyra. Our knowledge of the anat- 

 omy is due to the investigations of Leidy,Binney, Semper and Pfeffer. 

 Von Martens is in error in attributing a dart sack to this group, and in 

 placing it as a subgenus under Helix s. str. ; it is intimately allied to 

 Polygyra, the large appendix and split penis retractor being the only 

 anatomical features separating Praticolella from Polygyra, the texture 

 of the shell offering another differential feature. 



P. griseola Pfr., iv, 76. 

 P. ampla Pfr. cicercula Fer., Dh. 



ocampi Streb. iv, 76. pisum Beck. 



P. flavescens (Wiegm.) Pfr., iv, albocincta Binn. 



[75. albozonata Biun. 

 P. berlandieriana Moric. iv, 76. albolineata Old. 



pachyloma Mke. splendidula Ant. 



Genus POLYGYRA Say, 1818. 



Polygyra SAY, Journ. Acad. Nat. Sci. Phila, i, p. 278 (proposed 

 for auriculata, avara and seplemvolva). PILSBRY, Proc. Acad. N. S. 

 Phila. 1889, p. 193 ; 1892, p. 400. 



Plus Dcedalocheila BECK, Index, p. 21 (for auriculata, avara and 

 implicata). Triodopsis RAFINESQUE, Journ. de Phys., etc., Ixxxviii, 



