BY H. LEIGHTON KESTEVEN. 44& 



This is not only correct in point of nomenclature, but it will be 

 found more in accordance with a natural arrangement of the 

 groups if it is advantageous to split the genus up into systematic 

 divisions. 



Lotorinin {scmsu stricto) will embrace all those typical forms 

 which have been placed by Tryon under Simjndum, Cymatium^ 

 and Gutturtiium. The sections will then include a few forms 

 which cannot be regarded as in any way typical. 



The conclusions of this Part are that the following should be 

 adopted : — 



Family LOTORIID^, Harris. 



Genus Lotorium, Montfort. 



Part ii. — Arrangexment of the Species. 



"The original group has been considerably divided; in fact, 

 Bolten, Montfort, and others began the work of division. The 

 whole matter is worth an exhaustive discussion. ..." (Dall, 

 ' Blake Mollusca,' p. 225, 1889). 



In the following pages I discuss this subject at some length, 

 and have come to the conclusion that the whole of the species 

 included by Tryon in Triton {sensu stricto), Shn^ulum, Cymatiiim 

 and Gutturnium form one natural genus. From a study of 

 figures and descriptions, and of one species {P. scaber, King), I 

 feel inclined to regard Priene, H. & A. Adams, as a good genus. 

 I am unable to express any opinion as to the value of the various 

 fossil groups proposed by Fischer, Conrad, Gabb and others. 

 Epidromus ( = Cohihraria) has rightly been treated as a distinct 

 genus by most late w^riters. I agree with Dr. Dall that Fischer 

 (12, 655) incorrectly referred the Apollon group of Gyi^ineum 

 and Aspella to " Triton " as subgenera. 



In this essay I have used conchological and embryonic characters 

 only. I have, however, also studied the matter from an anato- 

 mical standpoint, and, although my investigations here have been 

 by no means extensive, I think it may safely be said that investi- 

 gations in this line will have no important modifying effect on 



