324 TESTA CE A ATLANTIC A. 



(§ XantUinus, Mouss.) 



Hyalina clymene. 



Zonites Clymene, Shuttle Ben,. Mitth. 138 (1852) 



Helix Clymene, Pfeiff., Mon. Hel. m. 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 oppidulum 

 Garachico, una cum Pupa, Physa, Ancylo, et Hydrocand 

 commixta, degens. 



I am extremely doubtful whether this curious little Planor- 

 bls-\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 that the H. Clymene 

 has hitherto been observed is near Garachico, 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 Hydroca'na 

 gutta. 



Genus 7. LEUCOCHROA, 1 Beck. 

 Leucochroa ultima. 



Leucochroa ultima, Mouss., Faun. Mai. des Can. 19.pl. 1. 



f. 34-36 (1872) 

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



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

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



