70 Mr. E. A. Smith on some new 



Eatonia, gen. nov. 



Testa forma? rissoidese ; apertura subcireularis ; peristoma simplex, 



continuum, margine labrali haud inerassatum. 

 Operculum ovatum, pauci- vel unispirale, nucleo subterminali a 



latere columellari paululum remoto, infra ossiculo prominenti a 



nucleo exsurgente et versus marginem columellarem extenso 



munita. 



There are two genera which have affinity to the present 

 one — Jeffrey sia and Rissoina. With Jeffrey sia it agrees in 

 the form and character of the aperture, but differs in having 

 the nucleus of the operculum not lateral, but situated within 

 the margin and towards the lower end — in fact, agreeing 

 in this respect with Rissoina (see Adams, ' Genera of Recent 

 Mollusca,' vol. iii. pi. 35. f. 1, a& b), but distinguished from 

 it by the absence of the basal faint channel of the aperture 

 and the lack of any incrassation to the labrum. 



The operculum of Jeffreysia is composed of concentric layers 

 (as in Purpura), commencing from a nucleus situated on the 

 margin of the inner or columellar side ; and the ossicle or 

 rib proceeds "from the nucleus in the direction of the outer 

 margin " (Jeffreys, ' Brit. Conch.' iv. p. 58 ; in the figure, I.e. 

 pi. 1. f. 3, it is apparently the reverse). 



In Eatonia the operculum is spiral, consisting of one or 

 more whorls, the nucleus is situated within the margin and 

 about one fourth the entire length from the lower end, and 

 the ossicle is directed towards the inner margin. 



I feel much pleasure in associating with this group the 

 name of the Rev. A. E. Eaton, who worked so indefatigably 

 in collecting specimens during the expedition. 



6. Eatonia Jeerguelenensis, sp. nov. 



Testa ovato-conica, tenuis, olivaceo-nigrescens, versus labrum palli- 

 dior semipellucida, vix rimata ; anfractus 6, convexi, lseves parum 

 nitidi, incrementi lineis striati, sutura simplici sejuncti ; apertura 

 fere circularis, longitudinis totius ■& aequans ; peristoma simplex, 

 continuum, in regione umbilicali leviter inerassatum et vix 

 reflexum. 



Operculum ovatum, intus concavum, nucleo posteriore sed haud ter- 

 minal^ crassiusculum, margine externo lira inerassatum, unispirale, 

 supra incrementi lineis vakle striatum, infra ossiculo elongato a 

 nucleo exsurgente munitum. 



Long. 3 mill., diam. 1^. 



Hob. On a sponge, Kerguelen's Island. 



This species was found in company with Rissoa Kergueleni. 

 It is of a very different form, the spire being conical, the last 



