322 TEST ACE A ATLANTIC A. 



it into the same group as the cellaria. This structure of the 

 umbilical region will at once serve to separate even the young 

 and nil mile examples from the crysUdlina, — from which it 

 further differs (apart from the larger stature of the adult shells) 

 in its basal whorl being relatively a trifle more widened 

 towards the aperture, in its under-parts being of a somewhat 

 more mill.// white (or rather less strictly glassy), and in its 

 volutions being more appreciably impressed towards the suture 

 with transverse radiating lines, — which become lighter, and 

 almost evanescent, posteriorly. 



The only district in which I am aware that the H. vermi- 

 culum has hitherto been observed (unless indeed the H. 

 semicostida, Beck, which is reported from Grand Canary, be 

 identical with it) is in the north of Teneriffe, — where it was 

 taken by Mr. Lowe and myself, in abundance, beneath stones, 

 on the dry calcareous ground between Eealejo and the Puerto 

 of Orotava, as also (at La Dehesa) immediately above the 

 latter. 1 



(§ Crystallus, Lowe.) 



Hyalina crystallina. 



Helix crystallina, Mull., Hist. Verm. ii. 23 (1774) 



„ „ Loive, Cambr. Phil. S. Trans, iv. 47 



(1831) 

 „ „ Alters, Mai. Mad. 17. t. 2. f. 18-21 



(1854) 

 „ „ Paiva, Mon. Moll. Mad. 22 (1867) 



Hyalina crystallina, Mouss., Faun. Mai. des Can. 17 



(1872) 

 Helix crystallina, Pfeiff., Mon. Hel. vii. 106 (1876) 



Habitat Fuerteventuram, Teneriffam, Palmam, et Hierro ; 

 hinc inde sub lapidibus in graminosis. 



I have no doubt that this little European Hyalina (which 

 has established itself also in the Madeiran and Azorean Groups) 

 will be found eventually to be universal at the Canaries, — 

 though hitherto it has been observed only in four islands, out 

 of the seven. In those four, however, I have myself met with 

 it, — namely at Sta. Maria Betancuria in Fuerteventura ; at the 

 Agua Mansa, the Agua Garcia, and near Orotava, in Teneriffe ; 

 in the Barranco de Agua and the Barranco de Galga, as well as 



1 I may just notice in this place the Hyalina semicostula, Beck, which is 

 cited bv Reeve from Grand Canary, but without any evidence for the correct- 

 ness of his habitat. I have little doubt that Reeve was mistaken in quoting 

 the species, which is said to occur in Portugal, as Canarian ; and I am glad to 

 observe that Mousson has arrived at the same conclusion. I have therefore 

 no hesitation in omitting it from our catalogue. 



