CANARIAN GROUP. 353 



Habitat Gromeram ; a Barone de Paiva communicata. Ra- 

 rissima. 



The H. Paivana, which appears to be peculiar to Gromera, 

 and which measures about 10 lines across its broadest part, is a 

 rather depressed but obtuse shell, there being no indications of a 

 regular keel ; its spire is only slightly raised, but somewhat 

 blunt and dome-shaped ; and its umbilicus is partially visible, it 

 being only half closed-over (or perhaps rather more) by the re- 

 flexed lamina of the peristome. It is somewhat thin in sub- 

 stance, tumid beneath, and of a yellowish-brown hue (paler on 

 the underside), but ornamented with four narrow and regularly 

 interrupted darker bands, which give a somewhat freckled ap- 

 pearance to the whole upper portion ; and the surface is beset 

 with coarse tubercles (which become obsolete towards the 

 nucleus, and gradually disappear below on the umbilical area 

 which is more shining and polished), caused by the breaking- 

 up of the densely-packed oblique transverse lines of growth. Its 

 peristome, which is acute and not much recurved, has the upper 

 and lower insertions slightly approximated. 



Helix Villiersii, 



Helix Villiersii, tfOrb., in W. et B. Hist. 57. t, 3. f. 11, 12 



(1839) 



Pfeiff., Man. Hel. i. 378 (1848) 



Villiersi, Mouss., Faun. MaL des Can. 79 (1872) 



Habitat Gomeram ; a Dom Despreaux olim reperta. 



As stated below, the ' var. a. subaucta ' of the H. quadri-* 

 cincta would seem to me to approach very near to this species 

 (which I have not been able to inspect, and which apparently 

 is but little known), though the acuteness of its keel prevents 

 it from being actually identified with it. Indeed, judging from 

 the diagnosis, the H. Villiersii is not more carinated than the 

 H. Planorbella, and probably not more so than the Paivana ; 

 and its transverse costate ridges are said to be interrupted be- 

 neath, and the whole shell thin and fragile. 



The H. Villiersii^ which was found many years ago in Gro- 

 mera by M. Despreaux, was also unknown to Mousson, who 

 nevertheless seemed inclined to believe that it may prove in 

 reality (when further material shall have been obtained) to 

 represent some variety, or state, of either the H. planorbella 

 or the H. quadrioincta ; though, I suspect, unless indeed the 

 description be very inaccurate, that it must be distinct from at 

 all events the latter. 



A A 



