CANARIAN GRO UP. 379 



' D'Orbigny's description of H. lancerottensis proves by his 

 original single type to have been drawn up from an old dead 

 bleached example of H. monilifera, Webb ! The figures, how- 

 ever, to which he refers (t. 1. ff. 24, 25) represent the true H. 

 lancerottensis of Webb, whose first two plates of shells had been 

 engraved under his own management by Terver long previous to 

 d'Orbigny's engagement in the work, and correctly exhibit the 

 species originally intended, and published by Webb in his Sy- 

 nopsis, but of which the present is unfortunately not the only 

 one subsequently misunderstood and thrown into confusion by 

 d'Orbigny' (1. c. 199). And, again (I. c. 200) ; 'D'Orbigny has 

 wonderfully misunderstood this common species. Not only, as 

 already noted, has he placed in his collection and described in 

 Webb's " Histoire " for the true H. lancerottensis, Webb, an old 

 dead shell of H. monilifera, 1 Webb ; but five genuine examples 

 of the true H. lancerottensis in his collection have been mis- 

 taken for, and actually stand as types of, the larger variety, H. 

 Orbignyi, Webb.' 



Although seldom very abundant, there is not a single shell 

 which is more universally spread, than the H. lancerottensis, 

 over the entire Canarian archipelago, in the whole seven 

 islands of which I have indeed myself taken it. It is extremely 

 variable, both in size and surface, putting on a slightly modified 

 phasis according to the local influences, especially dryness and 

 moisture, of the particular district in which it is found ; and I 

 cannot understand on what principle the Gomeran form of it, 

 which is perhaps a trifle more depressed and conspurcata-like, 

 should have been singled out by Mousson (under the title of H. 

 adoptata) for specific separation, thus destroying unnecessarily, 

 as it seems to me, by a single link, the chain of faintly differing 

 races which gives so marked a topographical interest to the 

 species as a whole. In Lanzarote and Fuerteventura it more 

 often assumes a rather small, bleached, and calcareous aspect, 

 free from all indications (even when immature) of minute hairs ; 

 and in the former of those islands I more particularly met with 

 it about the lofty cliffs (known as the Eisco) in the extreme 

 north, overlooking the Salinas, a locality which I happen to 

 know, from letters now in my possession, was comparatively well 

 searched by Mr. Webb, and where he evidently obtained the 

 examples which were figured as his types of the H. lancerotten- 

 sis. In TenerifTe the larger and thinner form, described by 

 d'Orbigny as the < H. Orbignyi, W. et B./ and in which the 

 surface is often minutely pilose, may perhaps be said to pre- 

 dominate ; though both phases of it (and every intermediate 



1 This specimen I have myself also examined accurately, and can vouch 

 for Mr. Lowe's observation being correct. 



