POLYGYRATIA. 83 



Section Systrophia Pfr., 1855. 



Shell yellowish or corneous, thin, the lip slightly expanded, often 

 having one or two teeth ; parietal callus slight, not elevated nor 

 toothed ; no internal lamellce. Type P. helicycloides d'Orb. (see pi. 

 20, figs. 41, 42, 43, P. stenogyra). 



Distribution : Brazil, Bolivia, Equador, Peru. 



P. calculina Pfr., iii, 125. P. pseudoplanorbis Lub., iii, 126. 



calculus Pfr. not Lowe. P. stenogyra Pfr., iii, 124. 



P. decagyra Phil., iii, 125. P. stenostrepta Pfr. 



P. gyrella Morel., iii, 126. P. systropha Alb., iii, 127. 

 P. helicycloides d'Orb., viii, 150. P. tortilis Morel., iii, 125. 



P. ortoni Crosse,iii, 127. P. wallisiana Mouss., iii, 126. 

 P. polycycla Morel., iii, 125. 



Section Entodina Ancey. 



Shell planorboid, many whorled ; lip narrowly expanded, tooth- 

 less or toothed, its ends connected across the parietal wall by an 

 elevated, toothed callus. Type P. reyrei Souv., pi. 20, figs. 39, 40. 



Distribution same as Systrophia. 



The parietal callus is shaped somewhat like that of Polytjijra 

 cereolus. 



P. cheilostropha d'Orb., iii, 128. P. janeirensis Pfr., viii, 150. 



P. entodonta Pfr., iii, 126. P. platygyra Alb. 



P. heligmoidea d'Orb., iii, 125. P. reyrei Souv., iii, 127. 



Subgenus? II. COXIA Ancey, 1887. 



Coxia ANC., Conchologists' Exchange, i, p. 75, June, 1887. Type 

 Helix macgregori Cox. Calostropha ANC., Conch. Exch. ii, p. 38, 

 Sept., 1887. Type Helix raffrai/i T.-C. 



. Shell many (about 10) whorled, the volutions acutely carinated at 

 periphery or shoulder, equally visible above and below. Spire either 

 flat, slightly concave, or conoidal. Aperture oblique, subquad- 

 rangular, the lip expanded and slightly thickened, its ends connected 

 by a parietal callus. Type P. macgregori, pi. 20, figs. 44, 45, 46. 



Soft parts of animal unknown. 



The shells in this group differ from those of the South American 

 many- whorled Helices in the flat upper surface of each whorl, and 

 its acute peripheral keel. 



