CAN AM AN GROUP. 367 



the other is smaller and at a little distance from it in the 

 direction of the dorsal line (the space between the two assuming 

 the form of a curved sinus). These teeth are naturally more 

 pronounced in some individuals than in others, and in the spe- 

 cimens from Taganana they are often monstrous ; and although 

 globose in outline, the posterior half of its basal volution is 

 distinctly keeled ; the apical portion of its spire is usually more 

 or less worn and decorticated ; and although there are no traces 

 of granules (properly so called], the surface will nevertheless be 

 seen, when viewed beneath a very high magnifying power, to 

 be beset here and there with infinitesimal spirally-arranged 

 granuliform markings, — as though composed of closely-packed 

 but fragmentary (or broken-up) lines. 



Helix nivarise, n. sp. 



T. imperforata, solida, subgloboso-depressa, malleata, superne 

 subopaca et sublente minutissime arenoso-granulata, subtus in 

 medio nitida egranulata et ibidem clare olivaceo-lutea, supra 

 obscurius luteo-olivacea et fasciis brunneis 3 vel 4 suffuse cincta ; 

 anfractibus 5^ convexiusculis, ultimo inflato (nee etiam postice 

 carinato), antice descendente ; apertura parva, subtriangulari- 

 Lunata, valde constricta ; peristomate albo, valde incrassato, 

 rudi, intus convexo, extus expansiusculo acuto reflexo, ad angu- 

 lum superiorem necnon inter angidum et lineam dorsalem plus 

 minus obsolete subdentato-calloso, margine basali lato subin- 

 sequali sed intus simplici recto. — Diarn. maj. 10| I'm; alt. Q\. 



Habitat Teneriffam ; in inferioribus juxta Portum Orotovse 

 a Eevdo. E. T. Lowe reperta. Necnon etiam semifossilis ibi- 

 dem exstat. 



Obs. — Ab H. malleata, Fer., nisi fallor, vere distincta. 

 Differt testa majore, subdepressiore, subdilutius (sc. minus laete 

 olivaceo-) colorata, ubique minutissime arenoso-granulata et 

 subopaca (nee lucida) ; anfractu ultimo nee etiam postice cari- 

 nato, antice lentius minusque descendente ; apertura multo 

 magis triangulari, peristomate intus magis convexo, sed extus 

 magis acuto producto recurvo, marginibus ad insertiones remo- 

 tioribus, dentibus binis dextri obsoletis, basali intus crassiore 

 magisque recto. 



It is somewhat singular that so large and conspicuous a Helix 

 as the present one should apparently have escaped the researches 

 of the many naturalists who have visited Teneriffe ; but if it be 

 right to separate the Grand-Canarian H. Glasianaand the Gome- 

 ran H. Fritschi from the malleata (of which, I think, there can 

 be but little doubt), it must be right, a fortiori, to deal in a 

 similar manner with the H. nivario3, for while those two forms 



