CAN AM AN GROUP. 341 



costoma and lactea types, and which was detected by Fritsch, 

 in a snbfossil condition, in Fuerteventura. ' Cette espece,' says 

 Mousson (I. c. 85, 86), 'que je ne connais que subfossile, pour- 

 rait au premier abord etre prise pour line forme dependante de 

 VH. lactea, MULL, mais un examen attentif demon tre qu'elle est 

 bien differente et rentre les Hemicycles du groupe sarcostoma. La 

 spire est plus regulierement conique que dans la lactea, de sorte 

 que le dernier tour a relativement moins de grandeur. La sur- 

 face est striee, non granuleuse, moins fortement au dernier tour, 

 lequel par contre presente sur toute sa surface un martelage 

 grossier, mais peu profond, qu'on ne voit pas dans les especes 

 mediterraneennes. Le bord superieur n'a pas de tendance a 

 s'evaser, mais est presque parallele au bord basal. Le peristome 

 est gros et s'arrondit en se reflechissant. Le bord basal est 

 epais, formant a Finterieur une ligne un peu relevee, se repliant 

 a l'exterieur et se collant largement sur la region ombilicale, qui 

 est renflee et calleuse.' 



Helix sarcostoma. 



Helix sarcostoma, W. et B., Ann. des Sc. Nat. 28. syn. 312 



(1833) 

 „ „ cCOrb., in W. et B. Hist. 54. t. 1. f. 13, 14 



(1839) 

 „ „ Pfeiff., Mon. Hel. i. 266 (1848) 



„ „ Mou88., Faun. Mai. des Can. 86 (1872) 



„ Pfeiff., Mon. Hel. vii. 343 (1876) 



Habitat Lanzarotam, Fuert event urarn, et Canariam Gran- 

 dem ; in montibus hinc inde haud infrequens. Necnon etiam 

 semifossilis in insulis iisdem reperitur. 



It is more particularly of the two eastern islands of the 

 archipelago, Lanzarote and Fuerteventura, that this large and 

 beautiful Helix (highly developed examples of which measure 

 about an inch across their broadest part) is characteristic; 

 nevertheless it occurs also, though much more sparingly, in 

 Grand Canary. It was in those three islands that it was origi- 

 nally detected by MM. Webb and Berthelot ; and it is in the 

 same three that it has subsequently been met with by Fritsch, 

 Mr. Lowe, myself, and others. I feel almost satisfied that it 

 does not exist in Teneriffe, and agree therefore with Mousson 

 that the habitat ' Teneriffe ' given by Zollinger is probably the 

 result of mere looseness and inaccuracy ; — ' La localite Tenerife,' 

 says he, ' me parait plus que douteuse, M. Zollinger ayant recu 

 cette espece, et ne l'ayant pas trouvee lui-meme.' It occurs 

 on the mountains at a rather high elevation. In Lanzarote we 

 found it principally at Chache and around Haria ; and it was 



