PYRAMIDULA. 43 



in temperate regions also, by higher groups of Helices. The latter 

 differ widely from these Patuloid genera in lacking parapodlal 

 grooves, in the solid, ribbed jaw, complex genital system, and other 

 features to be described later. 



In treating of the subgenus Patula it will be shown that that name 

 is not available as a designation for the present genus as a whole. 

 Pyramidula is the earliest name, and should be accepted. It may be 

 objected that no diagnosis of Pyramidula was published by Fitzinger, 

 but the same may be said of Beck's genera. Let those who repudi- 

 ate Beck's names cast the first stone at Fitzinger! 



Pyramidula is divisible into eight subordinate groups, which may 

 be tabulated thus : 



a. Shell lacking internal teeth or folds, 



b. Spire conical ; size very small, shell thin, Pyramidula s. s. 

 bb. Spire depressed, 



c. Shell rather large and solid, Patula. 



cc. Shell small or minute, 



d. Surface spirally lamellate, Lyrodiscus. 



dd. Body-whorl with 20-25 spaced oblique laminae, 



Planogyra. 



ddd. Surface striate or rib-striate, Gonyodiscus, Patulastra. 

 aa. Body-whorl having one or several pairs of internal teeth, 

 b. Internal teeth tubercular; surface spirally sculptured, 



Helicodiscus. 

 bb. Internal teeth lamellar ; surface obliquely sculptured, 



Atlantica. 



Besides these, another group, Pupisoma, has been referred provi- 

 sionally to this genus. 



Subgenus PYRAMIDULA Fitz. 



Shell small, moderately or widely umbilicated, lacking internal 

 folds or teeth. 



The following sections may be grouped under this subgeneric 

 head : Pyramidula s. sir., Patulastra, Planogyra, Gonyodiscus and 

 Lyrodiscus. 



Section Pyramidula Fitz., s. str. 



Pyramidula FITZ., Syst. Verz., p. 95. 



Shell minute, openly umbilicated, with pyramidal spire and obtuse 



