THE NATURAL HISTORY SURVEY. 



205 



b. Depressed, periphery slightly carinated, striae rib-like, 

 whorls marked by reddish flames placed;longitudin- 



ally . alternata 



B. Shell small. 



a. Aperture devoid of teeth, spire slightly convex striatella 



b. Aperture with from one to three teeth, spire flat.* lineata 



SUBGENUS PATULA Held, 1837. 



"Shell: Rather large and solid, with convex spire and 

 open umbilicus; whorls rounded or carinated at the periphery. 

 Surface striate, ribbed-striate or spirally ribbed, obliquely 

 flamed, unicolored or spirally banded; lip thin, simple." 



"Animal: Having a large foot, its length greater than the 

 diameter of the shell, the tail rounded; sole without any traces 



FIG. 47. 



Genitalia of PYRAMIDULA. (Filsbry, Guide to Helices, pi. xi, figs. 20, 

 21.) A, P. ALTERNATA Say. B, P. STRIATELLA Anthony. 



of longitudinal divisions; the foot margins having a wide bor- 

 der above, bounded by a distinct groove, the grooves meeting 

 overthe tail. Eye-peduncles long and slender, tentacles minute. 

 Mantle edge thick. Genitalia system (Fig. 47) simple, lacking 

 accessory organs. Penis receiving vas deferens and retractor 

 muscle at its summit. Spermatheca bulbous, its duct very 

 long. Ovisperm duct very much convoluted, the ovo-testis 

 consisting of small groups of large club-shaped follicles. Eye- 



