CANARIAN GROUP. 351 



growth; and such being the case, its affinities, which at first 

 sight are not readily apparent, will perhaps be ascertained to 

 lie amongst the forms around the H. planorbella, though, at 

 the same time, the species has evidently something in common 

 with the (equally Palman) H. granomalleata. 



Not to mention this peculiarity of its umbilicus, the pre- 

 sent species is smaller than the H. granomalleata, and it is 

 also rather more depressed both above and below, and it has a 

 fine thread-like though minute keel which is traceable even down 

 to the very aperture. It is not much malleated, its sculpture 

 consisting mainly (apart from the excessively minute sand- 

 like granules) of extremely irregular and densely-packed, coarse, 

 subconfluent, oblique ridges, or subundulating vermiform folds ; 

 and in colour it would seem to be of a dingy olivaceous-white, 

 suffused with a darker tint in consequence of the 4 or 5 obso- 

 lete bands which are indistinctly indicated. 



Helix Plutonia. 



Helix Plutonia, Lowe, Ann. Nat. Hist.vii. 108 (1861) 

 Pfeiff., Mon. Hel. v. 300 (1868) 



Mouss., Faun. Mai. des Can. 76. pi. 4. 



f. 12, 13 (1872) 



Pfeiff', Mon. Hel. vii. 423 (1876) 



Habitat Lanzarotam, et Fuerteventuram ; in ilia recens, sed 

 in hac et recens et vix semifossilis ad Pozonegro parce reperitur. 

 By M. Fritsch this well-marked Helix was found both in 

 Lanzarote and Fuerteventura, but it is only in the latter 

 that it was obtaiued by Mr. Lowe, -who took several subfos- 

 silized examples of it (for I think that they are more than 

 merely dead and bleached), along with one or two others im- 

 mature and recent, at Pozonegro, on the eastern side of that 

 island ; but it is a species which I did not myself meet with. 



The H. Plutonia is a large, rather flattened, obtuse, 

 and almost sublenticular shell, nevertheless with the nucleus 

 of the extremely compact and closely-set spire somewhat pro- 

 minent, and with scarcely any indications of a keel on the 

 ultimate volution, though there are evident traces of one up 

 the spire, manifested by a thread-like, subelevated, laterally- 

 compressed line along the anterior edge of the suture. Its 

 umbilicus is generally half-exposed, and thus far therefore 

 open, but at times it is nearly closed up by the reflexed lamina 

 of the columella ; its whorls are six in number, and all of them 

 except the basal one much flattened ; and its upper surface is 

 covered with fine and light, irregular, scabrous, costate lines, 

 intermingled with a few granules, whilst, beneath, it is more 



