U4 MR. G. NEVILL ON THE [Feb. 17, 



surface^ of a closely allied, even more characteristic form : spire pro- 

 duced, whorls more convex, the last one perfectly rounded, with its 

 base quite convex ; aperture as in var. (/rimaldiensis ; it appears to 

 have been less smooth. 



Alt. 21, diam. 27| millim. 



Measurements below from Pfelffer, Mon. i. p. 273 : — 



Alt. 21, diam. maj. 35, min. 27 millim. 



Helix (Campyl/Ea) MA^TRELIANA, Bourg. MS. (Note compl. 

 sur des Moll., Mammif. &c., Cav. prfes de Vence, 1868, p. .5, name 

 only). 



I am indebted to Mons. Bourguignat for the following Latin 

 diagnosis: — 



" T. profunde angusteque umbilicata ; depressa, subtranslucida, 

 argute siriatnla, nunc surdo-albida, olim corneo-viridescenti ac 

 zonuUs tribus intensioribus (qiiarum duce superiores, angustcc ; 

 tertior inferior, lata, ad regionem umbilicalem evanescens) cir- 

 cumcincta ; spira depressa, parum convexa; apice ohtusissimo, 

 sat valido, argutissime granulato ; anfractibus 6 regularUer sen- 

 simqne crescentibus, supra convexis ac sutura profunda separatis ; 

 •ultimo validiore, compresso-rotundalo, prope aperturam levifer 

 coarctaio, ac ad inscrtionem labri vix descendente ; apertura 

 parum obliqua, lunata, externe rotundata, infra rectiuscula vel 

 arcuata ; peristomate acuta, patulo ac rejlexo ; labro supero vix 

 reflexo ; labro columellari brevissimo, circa regionem umbili- 

 calem dilatato. 



"Alt. 11-12. diam. max. 21-23 millim. 



" Caverne Mars, pros de Vence, Alpcs-Marit." {CI. J. R. Bour- 

 guignat, in litt.) 



Var. ROBUSTA, G. Nevill. 



Fairly abundant in deposits A, B, D, and E, but very difficult to 

 obtain any thing like perfect specimens. The Menton specimens are 

 rather larger and of a more robust variety than the typical Vence 

 form. In deposit A a subvar, minor was not uncommon, with more 

 compressed whorls, less produced (almost rounded) aperture, and 

 less open umbilicus, the columellar margin a good deal less oblique. 

 A very characteristic feature in Menton specimens of //. maureliana 

 are the often very conspicuous " varices," especially noticeable in 

 young specimens, as in Nanina, section Bensonia {N. monticola, &c.) ; 

 "this, of course, is due to a thickening within the peristome, at dif- 

 ferent periods of growth, only partially absorbed when the animal 

 recommences the growth of its shell. Mons. Bourguignat writes 

 me that its nearest ally is H. sonata, Studer, of which he is inclined 

 to consider it as " una forme atavique." It differs materially from 

 all the varieties I know of H. planospiru. 



Var. robusta, from deposit I) (figured). Alt. 13^, diam. 25| 

 millim. 



Subvar. apprcssa, from deposit D, Alt. 12^, diam. 23| millim. 



