MADEIRAN GROUP. 67 



account, perhaps, it might be more natural to conclude that at 

 any rate some few of the forms have really passed away, even 

 whilst the tendency of every renewed observation is to lessen 

 the number of those which were supposed to be extinct. In- 

 deed one of the most anomalous of all the land-shells which 

 have yet been brought to light — the Helix delphinula of 

 Madeira proper, which teems in the calcareous drift near 

 Canical — has up to the present moment altogether eluded 

 detection in a recent state, and we might almost therefore be 

 justified (considering its comparatively large size) in assuming 

 it to belong exclusively to a passed epoch had not the discovery 

 by Mr. Lowe of a form scarcely less conspicuous (the somewhat 

 cognate H. delphinuloides), so recently as in 1860, rendered it 

 at least possible that even the H. delphinula may still survive 

 in some elevated, remote, sylvan ravine, and may yet reward 

 the researches of future naturalists. But if this should ever be 

 the case, we may confidently anticipate that it will be found, as 

 it were, only just to linger on, in some area of the most reduced 

 dimensions and perhaps well-nigh inaccessible. And the same 

 remarks may hold good for a few other species, such as the 

 H. Botvdichiana, Fer., — which abounds in the conchyliferous 

 deposits both of Madeira and Porto Santo ; for, although it is 

 within the range of possibility that it may represent nothing 

 more than a gigantic quondaon-'pha.sis of Sowerby's H. punctu- 

 lata (which is common in Porto Santo and on one of the 

 Desertas), nevertheless since the latter has not hitherto been 

 observed at all in Madeira proper, the extreme abundance of 

 the H. Boivdichiana in the Canical beds places the species in 

 much the same category as the H. delphinula, — which is 

 equally plentiful at Canical, but which (in like manner) is un- 

 known to the recent fauna of the central island (and indeed, in 

 this particular instance, to the fauna of the whole group). 

 There is also a minute Achatina (or, more probably, a Lovea, 

 as lately defined by Mr. Watson) to which attention might be 

 drawn, as having escaped discovery in a living condition, and 

 the characters of which are sufficiently peculiar to render it an 

 important member of the general catalogue, — namely the 

 A. cylichna of Madeira proper ; and amongst the other Helices, 

 as yet exclusively subfossilized, which we may hope will be 

 made, sooner or later, to augment the recent fauna, I might 

 single out the little Helix arcinella, Lowe, so common at 

 Canical, and the curious H. coronula, Lowe, from the southern 

 Deserta, or Bugio. 



If we add to these five species (namely the Helix Bowdich- 

 iana, arcinella, delphinula, and coronula, and the Lovea 

 cylichna) the following seven — Helix chrysomela, Pfeiff., 



F 2 



