GASTROCOPTA, NORTH AMERICA, WEST INDIES. 65 



Habitat in Pennsylvania. Is it not likely a variety of P. pro- 

 ceraf (Pfr.). 



Pupa carinata Gould, from Maryland, was subsequently 

 said by Gould to be an immature or broken procera. 



I8a. Form riparia (n. f.), pi. 12, fig. 6. Columellar lamella 

 shorter, no callous or nodule below it. Teeth whitish, the 

 palatals usually smaller than typical. Calera and Big Will's 

 Valley near Valley Head, Alabama (H. H. Smith), and Gal- 

 veston, Texas (type loc., Pilsbry). 



18&. G. PROCERA DUPLICATA (Sterki). PL 12, figs. 7, 8; pL 

 13, fig. 7. 



The shell differs from procera by having the angulo-parietal 

 lamella more complex, due to the less complete concrescence 

 of the two component lamellae; the anterior end of the pari- 

 etal is visible as a low, callous branch directed towards the 

 columellar insertion (pi. 13, fig. 7). The parietal callous 

 between ends of the lip is usually thick. The tubercle below 

 the columellar lamella is typically strongly developed. Peri- 

 stome and crest as in procera, of a very pale brown tint, and 

 the callous thickening is heaviest a little inward from the edge* 



Length 2.9, diam. 1.2 mm.; nearly 6 whorls (typical). 



Length 2.25, diam. 1 mm. (smallest paratype). 



Distribution. South Dakota to the Rio Grande. Type 

 locality, Glenrose, Somerville Co., Texas. 



Bifidaria dupUcata STERKI, Nautilus, xxv, Feb. 1912, p. 116. 



It may be that this form of the subarid region deserves 

 specific rank, but the difficulty of distinguishing many speci- 

 mens from procera, owing to intermediate degrees of develop- 

 ment of the angulo-parietal lamella, causes me to consider it 

 a subspecies. It varies in size in each colony, as usual in the 

 group. Around New Braunfels, Texas, where it is common, 

 the maximum length is 3.3 mm., with barely 6% whorls. 



Localities for typical duplicate are : South Dakota : Wash- 

 ington Co. (Over). Oklahoma: Fort Gibson (A. D. Brown 

 coll.). Arkansas: Rogers, Benton Co. (Pilsbry and Ferriss). 

 Texas: Glenrose, Somerwell Co. (type loc.); Austin; San 

 Marcos, Hays Co. ; New Braunfels, Comal Co. ; near Hondo, 



