DRYMJKUS. XXXIX 



Z. navicula Wngn., xi, 186. /. aiirislrporis Bni<r., xi, 189. 



N. fasciata Spix. B. la got is Mke. 



v. lateritius Pils., xi, 320. Auricula leporis Lam. 



Z. involutus Mart., xi, 187. Stenostoma auritum Spix. 



Z. uranops Pils., xi, 188. f. intension Pils., xi, 190. 



Z. lateralis Mke., xi, 188. Z. anrismuris Moric., xi, 191. 



Helix uniangulata Fer. 



Genus DRYMyEUS Albers, 1850. 

 Drymxus ALB., Die Hel., p. 155, types B. xanthostoma and B. 



hygrohylseus. PILSBRY, Manual, xi, p. 191. 



In this group the shell is generally of lighter structure and brighter 

 color than in Bulimulus. With the exception of the aberrant sub- 

 genus Leiostracus, all of the species have a characteristic pattern 

 of apical sculpture, consisting of minute pits arranged with great 

 regularity in spiral and vertical lines. 



The external anatomy, free muscles, and pallial organs are prac- 

 tically identical with those of Bulimulus (pi. 54, fig. 40, D. acervafus 

 Pfr., x 2). The secondary ureter is closed nearly to the end. The 

 genital system is similar to that of Bulimulus. 



The jaw is strongly arched, thin and flexible, composed of many 

 narrow plaits, narrowly imbricating, and obliquely converging toward 

 the median line, usually leaving a triangular plait or several short, 

 wedge-shaped plaits in the middle. The lower or cutting margin is 

 often more or less serrate (pi. 50, fig. 1, D. virginalis, after Schako; 

 pi. 58, fig. 69, D. acervatus). 



Radula rather broad, with a great number of teeth, 115 to over 

 150, in each transverse row. The rows are more or less angular in 

 the middle, but not markedly V-shaped (pi. 50, fig. 2, D. virginalis, 

 after Schako; pi. 58, fig. 75, D. acervatus, inverted). 



The lateral teeth are oblique, tricuspid, the ento- and meso-cones 

 more or less united basally ; the ectocones become split upon the outer 

 laterals and the marginal teeth. The rhachidian tooth varies widely, 

 being tricuspid in some, unicuspid in other species (pi. 58, figs. 77, 

 79, D. acervatus; pi. 60, figs. 14, 15, D. vincentinus; pi. 60, fig. 16. 

 D. inter purictus}. In general, the lateral and marginal series of teeth 

 are scarcely differentiated, all the side teeth being practically of one 

 type. Distribution, tropical and subtropical regions of America, 

 living chiefly on plants. 



