86 Prof. A. Mousson on the Molluscan Fauna of the Canaries. 



they are, however, somewhat more globose in diameter, stronger, 

 and more chalky. All the other characters agree closely. 



5. Helix monilifera, Webb. I consider an example found in 

 Lanzarote to be the true species brought by Mr. Webb from the 

 same place, to which the preceding, at all events, is nearly allied. 

 The shell is, however, still somewhat more globose than in the 

 last, somewhat larger, white and chalky, with less distinct stria- 

 tion, but distinct scar-like impressions, especially beneath, and 

 moreover somewhat shining. The dark bands are less connected 

 together, broken up into dots ; the perforation appears nearly 

 closed by the reflexion of the lip, which extends from the colu- 

 mella to beyond the base. A somewhat strong white lip is con- 

 tinued round and within the peristome. 



6. Helix Despreanxii, D^Orb. The original form comes from 

 Canaria; the one brought by Herr Hartung, which, notwith- 

 standing some aberrations, seems to me to be only a variety, 

 from Lanzarote. Its differences may be stated as follows : — 



Var. moderata, MSS. 

 Testa depresso-couica, fortiter perforata, bicarinata, carinis magis 

 compressis et productis, secuuda subtiliore ; basis tuberculis gra- 

 riosis ornata. 



The essential characters are those of the species, only less 

 marked. The shape is altogether more depressed, with a flat, 

 prominent primary keel, which seems to be rather erose than 

 granulate-toothed ; the second keel, in some examples, is but 

 little prominent, in others as strong as the first ; the close-set 

 wrinkled warts of the under side assume more the appearance of 

 coarse granulations on a finely striated ground. One of the 

 examples has the upper side dark, contrasted by a white keel. 



7. Helix paupercula, Lowe. This little species, remarkable for 

 its much depressed form, and round constricted aperture, pre- 

 sents itself in tw^o varieties. \n the Azores (island of Fayal), 

 and in its subfossil, rarely living, state in Porto Santo, it is 

 smaller and flatter, with a less granulated surface, but especially 

 with an aperture contracted by a wart-like tooth pi'oceeding 

 from the thickened lip of the right border. The prevalent living 

 form in Porto Santo has scarcely an indication of the wart ; 

 that of Madeira is entirely destitute of it, with the shape less 

 flatly depressed, the umbilicus narrower, the last volution less 

 angular and more convex beneath, the aperture less horizontal, 

 the upper surface more distinctly shagreened. This second 

 variety was found in a few examples amongst the present speci- 

 mens from Lanzarote. 



8. Helix sarcostoma, \Vebb. This well-known handsome spc- 



