324 TEST ACE A ATLANTIC A. 



(§ Ncmtilimis, Mouss.) 



Hyalina clymene. 



Zonites Clymene, Shuttl., Bern. Mitth. 138 (1852) 



Helix Clymene, Pfeiff., Mon. Hel. iii. 11 (.1853) 



Hyalina Clymene, Mouss.^ Faun. Mai. des Can. 19, pi. 1. f. 



28-33 (1872) 

 Helix Clymene, Pfeiff., Mon. Hel. vii. 182 (1876) 

 Habitat Teneriffam ; ad rupes aquaticas juxta oppidiilum 

 Garachico, una cum Pupa, Physd, Ancylo, et HydroccBud 

 commista, degens. 



I am extremely doubtful whether this curious little Planor- 

 bis-\ike shell should be associated with Hyalina ; nevertheless 

 since it is considered by Mousson to be better placed here than 

 elsewhere, I will not disturb the situation which he has 

 assigned to it. But I will merely add, that its whole structure 

 appears to me to be distinct from that of the Hyalinas ; whilst 

 its subaquatic mode of life (on dripping rocks, in company with 

 Ancylus, Physa, and Hydroccena) is quite unprecedented, so 

 far as I am aware, in the members of the present group. 



The H. Clymene (the largest examples of which are, in their 

 broadest part, about a line across) is a flattened, Planorbis- 

 shaped little shell, slightly transparent, and of a dark olivace- 

 ous-brown, — often a good deal corroded with a hard whitish 

 deposit. Its volutions are transversely striated, and the ultimate 

 one is very largely developed — (the upper lip of the aperture 

 being more forwardly-produced than the lower) ; its spire is not 

 merely depressed, but absolutely concave ; and its umbilicus is 

 wide, and spirally visible from beneath. 



The only region in which I am aware tliat the H. Clymene 

 has hitherto been observed is near Grarachico, in the north of 

 Teneriffe. I did not myself meet with it ; but it was taken by 

 ]Mr. Lowe (as it had been, apparently, a few years before, by 

 Blauner) from off wet rocks, close to the waterfall, on the road 

 leading to Ycod de los Vinhos, — namely adhering to bits of 

 stick, &c., in trickling places, along with the Pupa castanea, 

 the Ancylus striatus, the Physa acuta, and the Hydrocoiua 

 gutta. 



Genus 7. LETJCOCHEOA,' Bech. 



Leucochroa ultima. 



Leucochroa ultima, J/oiiss., Faun, Mai. des Can. 19.pl. 1. 



f. 34-36 (1872) 

 Helix ultima, Pfeiff., Mon. Hel. vii. 193 (1876) 



' In some observations on the present genus, Mousson (I.e. 19) remarks: 

 ' Les Leucochroes, Beck, ou Calcarines, Moq.-Tand., forment un ensemble 



