MADEIRAN GROUP. 165 



open. In its normal aspect, however, the H. turricula is 

 alDundantly removed from even the vernietiformis. 



As will be inferred from the above remarks, the affinities of 

 the H. turricula are, most unmistakeably, with the four pre- 

 ceding and two following species, — its carinated volutions and 

 granulose, reddish-brown surface (the lower portion of which 

 has a tendency, when cleansed from the earthy dust with which 

 it is generally obscured, to be more or less indistinctly fasciated, 

 whilst the upper parts are usually marbled with a few irregular, 

 suffused, ill-defined, longitudinal, sometimes confluent blotches), 

 added to the smallness of its umbilicus, its circular aperture, 

 and its thin, elevated, continuous peristome, assigning it, with- 

 out the slightest doubt, to the little assemblage of Porto- 

 Santan forms to which Mr. Lowe applied the subgeneric title 

 of Hystricella. Yet as a species it is conspicuously distin- 

 guished from them all, — its extremely elongate, turret-shaped 

 spire and numerous volutions (which have a keel, very largely 

 developed in the ^ a. pererosa,'' ^ in the centre of each, causing 

 the basal volution to be strongly bicarinated), in conjunction 

 with the coviparative fineness and closeness of its granulations, 

 giving it a character which it is difficult to mistake^ 



Helix Leacockiana, n. sp. 



T. trochiformis, subtus planata perforata, undique granulis 

 obtusis densissime obsita, pallide brunneo-subflavescens sed 

 fasciis (prresertim subtus) nebulisque irregidaribus (praesertim 

 supra) rufo-brunneis hinc iude suffuse marmorata ; spira sat 

 elevata ; anfractibus convexis, bicarinatis, ultimi (subtecti- 

 formis) carina exteriore acutissima valde exstanti, interiore 

 obtusa rotundata recedente rarius obsoleta; umbilico puncti- 

 formi ; apertura subovali-rotundata^ labris continuis conjunctis, 

 peristomate simplici expanse subrecurvo tenui relevato. — Long, 

 axis If lin.; diavi. 2^. 



Obs. Species H. bicarinatce, Sow., affinis, sed differt testa 

 multo minus grosse sed etiam subdensius granulata, granulis 

 minutioribus obtusioribus (nee spiniformibus) , anfractu ultimo 

 sensim latiore subtectiformi, sc. carina exteriore multo magis 



' This particular state, which would seem to have escaped the observation 

 of Mr. Lowe, passes imperceptibly into the other ; nevertheless since it is 

 remarkably different in its ex;treme (or exaggerated) condition, from what 

 Mr. Lowe described as the normal one, I think perhaps it may be desirable 

 to define it briefly as follows : — • 



H. turricula, Lowe ; var. ;8. j^ererom. — Plerumque obscurior, spira breviore, 

 anfractibus in medio multo grossius carinatis (carina aJtissimii), ultimo sensim 

 latiore necnon antice obsolete subtortuoso, fere quasi superimposito, apertura 

 submajore. 



