310 HELICIGONA. 



Section Metacampylcea Pilsbry, 1894. 



Shell solid, sublenticular, acutely keeled, the spire obtuse-conic. 

 Aperture oblique, subrhombic ; outer and basal lips reflexed, thick- 

 ened within, the columellar insertion dilated, partly or wholly clos- 

 ing the narrow umbilicus. Surface minutely granulate, and with 

 larger papillae disposed in quincuncial order. Type H. rahtii A. 

 Braun, pi. 71, figs. 45, 46. 



In its acute carination, the lower Miocene H. rahtii is comparable 

 to H. lapicida or banatica of the recent fauna, but its sculpture is 

 that of H. setosa Zgl. The lip differs somewhat from that of any 

 living " Campylsea," but not more than various species of that 

 group differs from one another. Metacampylcea probably stands in 

 much the same relation to Tropidomphalus as Helicigona (lapicida} 

 does to Chilostoma (planospira, etc.). 



H. papillifera Klika and possibly H. obtusecarinata Sandb., are to 

 be referred here, but the latter may belong to the ancestral Tachea 

 stock. 



Subgenus GALACTOCHILUS Sandberger. 



Galactochilus SANDB., Land und Siisswasser Conchyl. der Vor- 

 welt, p. 387 (for H. pomiformis, mattiaca, ehingensis and cornumili- 

 tare). 



Shell subglobose, with low, conoid spire of about 4J whorls, the 

 last large with rounded periphery, subangular around the narrow, 

 partly or nearly closed umbilicus, slowly descending in front. 

 Aperture truncate-oblong, oblique ; lip obtuse, expanded on outer 

 and basal margins, dilated at columellar insertion, partly closing 

 the umbilicus. Surface smooth except for growth-strise. Type H. 

 ehingensis Klein, pi. 71, figs. 47, 48. 



This group contains several species from the lower Miocene, H* 

 pomiformis A. Braun, Ehingensis Kl., mattiaca Stein. I am dis- 

 posed to believe it an off-shoot from the " Campylsea " phylum. 

 Some specimens of H. arbustorum exhibit much the same subangu- 

 lation around the umbilical region. 



Subgenus MESODONTOPSIS Pilsbry, 1894. 



Shell large, depressed, with convex and very obtuse spire and 

 covered umbilicus. Whorls 5, convex, the last ornamented with two 



