398 TEST ACE A ATLANTIC A. 



under the name ' var. immodica,' as follows : ' Crassior, spira 

 magis elevata, rugis et nodulis minus numerosis sed fortioribus, 

 apertura parvula, peristomate obtuso incrassato integro sub- 

 soluto ; ' but it does not seem to apply to the subfossilized 

 specimens which we met with at El Charco, and which do not 

 differ appreciably from their recent homologues* However an 

 example is now before me, which was found (subfossilized) by 

 Mr. Watson, I believe near Las Palmas, and which answers in 

 every respect with the diagnosis of Mousson's variety. 



In outline the H. Despreauxii is conical and trochiform ; its 

 colour is a dusky cinerous- or plumbeous-white, but a rich casta- 

 neous-brown inside the aperture ; its perforation is small and 

 punctiform ; and its surface is much roughened with large irre- 

 gular scabrous tubercles and vermiform flexuose callosities, which 

 are more particularly coarse and conspicuous on the under side. 

 Its main feature however consists in its elegantly, equally, and 

 very deeply dentate keel, which is not only traceable up the 

 spire but is supplemented by a second keel, of a similar kind 

 but a little less prominent, in the middle of each whorl. The 

 shell is solid in substance, and has the nucleus brown and 

 corneous ; and its aperture is much angulated externally, with 

 the margins of the peristome a good deal approximated. 



Helix moderata, 



Helix Despreauxii, var. moderata, Mouss., Schw. Denksch. 



xv. 135 (1857) 

 moderata, Id*, Faun. Mai. des Can. 50. pi. 3. f. 4-6 



(1872) 

 Pfei/., Mon> Hel. vii. 250 (1876) 



Habitat Lanzarotam, et Fuerteventuram ; a DD. Hartung 

 et Fritsch lecta. 



I possess four examples of this Helix which were taken in 

 Fuerteventura by M. Hartung, and which were given by him to 

 Mr. Lowe in 1855 ; and although I have little doubt that the 

 H. moderata is in reality but an insular phasis (peculiar to 

 Lanzarote and Fuerteventura) of the Grrand-Canarian H. Des- 

 preauxii, nevertheless since the two forms are not likely ever 

 to be absolutely connected, and the one now under consideration 

 has been described by Mousson as specifically distinct, I will 

 not actually unite them. Judging from the types before me, 

 the H. moderata' may be said to be a trifle larger, paler, and 

 more depressed than the Despreauxii (the spire being less 

 elevated), and to have both its tubercles and callosities less ex- 

 aggerated or prominent, indeed the upper, or medial, keel of 

 the volutions is so far reduced in coarseness as sometimes to be 



