148 CORILLA. 



retractor being inserted on the uterus (pi. 42, fig. 38, C. erronea). 

 This species is ovoviviparous, the uterus in the individual figured 

 containing two young, having a membranous shell of about 5 mill, 

 diam., and more than 3 whorls. 



The shell differs from that of Pleetopylis in lacking internal barriers 

 transversely obstructing the passage. When internal lamellae are 

 present in Gorilla they run parallel to the sutures or nearly so, as in 

 Polygyratia. The central teeth are not smaller than the laterals as 

 in Pleetopylis, and there are further differences in the genitalia. All 

 of the species are from Ceylon. 



( Group of C. erronea : Parietal fold and internal plicae present). 



C. erronea Alb., iii, 157. C. anax Bens., iii, 157. 



C. rivolii Desh., iii, 156. C. odontophora Bens., iii, 157. 



carabinata Fer. 



(Group of C. charpentieri : no parietal fold or internal plicae). 



C. charpentieri Pfr., iii, 156. C. humberti Brot, iii, 156. 

 v. hinidunensis Nev. 



The nine genera following possess certain features in common, 

 binding them into a great group which the writer, in 1890, named 

 MACROON. The literature throwing light upon the anatomy and 

 affinities of the members of this super-generic group is very re- 

 stricted, three authors only having discussed them from the broad 

 standpoint of modern Helicology. SEMPER, in 1873, recognized 

 the alliance between Aeavus and Panda (with which he also groups 

 Gorilla and Caryodes) shown in the short kidney, simple genitalia, 

 smooth jaw and unicuspid teeth. PiLSBRY,in 1890, announced that 

 Aeavus, Panda, Helicophanta and Stylodonta agreed in having eggs 

 of extraordinary size, in which the young undergo prolonged ante- 

 natal development, and the shell actually attains a moiety of its 

 whorls before the independent existence of the creature begins. 

 HEDLEY, in 1892, studied the Australian forms, directing attention 

 to features of their eggs, embryonic shells and anatomy not before 

 appreciated, and gathering into one assemblage Panda, Pedinogyra, 

 Caryodes, Anoglypta (and Liparus). 



The group, as it is herein understood, contains snails with helicoid 

 or bulimoid shells, viviparous or with large, hard-shelled eggs ; the 



