42 EXDODONTID^. 



" Eadula (1) having only the mesocones developed upon central 

 and inner lateral teeth, or (2) having the centrals tricuspid, 

 laterals hicuspid lacking the entocones, marginal teeth similar but 

 with short basal-plates ; tliis being the usual form. In some 

 species the marginal teeth are multicuspid by the splitting of 

 their ectocones. 



"The dentition as usual, shows considerable variation, even in 

 species otherwise closely related. As a general rule, the lateral 

 teeth completely lack entocones, differing in this respect from 

 Trachycystis and the Endodonta-Charopa series ; but in the 

 section Helicodiscus, entocones are well developed. The dentition 

 is quite unlike Trachycystis in the form of the marginal teeth. 



" The genus Pyramidtda consists of dull-coloured ground-living 

 snails, species of which occur over the whole northern temperate 

 land area. Its nearest relatives are CJiaropa, Trachycystis, and 

 Stejjhanoda, genera occupying the southern temperate regions of 

 Australasia, Africa, and Soutli America respectively. All may be 

 regarded as the remnants of an early fauna, now replaced in the 

 tropics, and to a large extent in temperate regions also, by higher 

 groups of Helices. The latter differ widely from these Patuloid 

 genera in lacking parapodial grooves, in the solid, ribbed jaw, 

 complex genital system, and other features. 



" In treating of the subgenus Patida it will be shown that that 

 name is not available as a designation for the present genus as a 

 whole. Pyramidida is the earliest name, and should be accepted. 

 It may be objected that no diagnosis of Pyramidida was published 

 by Fitzinger, but the same may be said of Beck's genera. Let 

 those who repudiate Beck's names cast the first stone at 

 Fitzinger ! " (Pilsbry.) 



Section Pthamiul'la, Fitzinyer, s. str. 

 Pyramidida, Fitzinger, op. cit., p. 95 ; Pilsbry, toni. cit., p. 43. 



Type, Helix rupestris, Drap. 



Ranye. Europe and Central Asia. 



" Shell minute, openly umbilicated, with pyramidal spire and 

 obtuse smooth apex. Whorls tubular, obliquely striated. Aper- 

 ture round or nearly so ; lip simple. 



" Jaw arcuate, finely striated vertically. 



" Eadula having the central teeth uuicuspid, the side cusps 

 being represented by a slight sinuation. Laterals bicuspid. 

 Marginals with low wide basal-plate, the inner bearing two cusps, 

 the outer becoming multicuspid by splitting of the cusps. 



"This section differs from Gonyodiscus and Patulastra in having 

 the spire conically elevated, and from the former in lacking 

 rib-striae." (Pilsbry.) 



Only two species are known from the Indian Peninsula, and a 

 doubtful one from Ceylon, these being the most southern outliers 

 of the section. 



