﻿PROSOBRANCHIATA. 



349 



vel reticulatis tenuissimis ornatd ; aperturd semilunari ; columella arcuatd, in medio 

 denticulatd. 



Diameter, -j^ths of an inch. 



Locality. Headon Hill (S. Wood). 



This is a fossil of which I have myself found several specimens at the above locality. 

 It resembles N. aperta in outward form, its most material difference consisting in its 

 having six or seven very distinct ridges or cannula? not quite equidistant, and some- 

 what rounded, but these the artist has unfortunately not sufficiently shown m the figure. 

 No one, however, on comparing specimens with those of aperta, would fail to perceive 

 these cannulas. 



No. 273. Neritina planulata, F. E. Edwards, MS. Tab. XXXIV, fig. 21 a, b. 



Neeetina planulata, J. Lowry. Chart Brit. Tert. Foss., pi. Hi, 1866. 



— — Sandberger. Land- und Siissw.-Conch., p. 268, t. xv, fig. 14, 



1872. 



Spec. Char. " Testa globosd, apice obtuso, paulo eroso. Anfractus tres infra suturas 

 tenuissimas subi?npressi, ceterum convexi, nitidi, Jlavidi, guttulis albis aquoliter conspersis 

 aut seriatim deposiiis variegati ; ultimus ceteris omnibus quadrato altior. Aperturd 

 paulo obliqud semilunari, margine dextro et basali tenui, acuto, pariete et columella callo 

 nitido, leviter concavo, intus media parte plica supremd maxima et duodecim minoribus 

 obtusis munito obtectis. Operculum semilunare, in/erne apophgsibus duabus arcuatis 

 discrepantibus armatum." — Sandberger. 



Height, -^ths of an inch. 



Locality. Headon Hill {Edwards). 



A very determinable figure is given of a shell under the above name by Mr. Lowry, 

 who tells me it is a MS. name given by Mr. Edwards. This has been figured and 

 described also by Sandberger from a specimen sent to him by Mr. Edwards. Our shell 

 is prettily ornamented with diagonal and dark wavy lines. I have not the species. 



Genus 33?y/. — Nerita. Adanson. 

 For generic characters see ante, p. 342. 



No. 274. Nerita tricarinata, Lamarck. Tab. XXXIV, fig. 22 a, b. 



Nekita tricarinata, Lamlc. Ann. du Mus., torn, viii, pi. lxii, fig. 4 a, b, 1806. 

 — — Desk. Coq. foss. des Env. de Par., t. ii, p. 160, 1824. 



