250 TEST ACE A ATLANTIC A. 



and which I obtained from the (likewise eastern) region be- 

 tween Sta. Cruz and Canipo, but which differs from the Lea- 

 cockiana by being (inter alia) rather larger and less fragile, as 

 well as by its apex being more pointed, by its penultimate 

 volutions being relatively shorter and more flattened, by its 

 columella (although less posteriorly-dilated) being more flexuose, 

 and by its entire surface being appreciably iridescent. 



( Fusillus, Lowe.) 

 Lovea gracilis. 



Helix gracilis, Lowe, Cambr. Phil. S. Trans, iv. 61. t. 6. 



f. 28 (1831) 

 Achatina gracilis, Pfeiff., Man. Hel. ii. 284 (1848) 



7. vitrea, Lowe, Proc. Zool. Soc. Lond. 



200(1854) 



Glandina gracilis, Alb., Mai. Mad. 56. t. 14. f. 24, 25 (1854) 

 Achatina gracilis, /3. vitrea, Paiva, Mon. Moll. Mad. 107 

 (1867) 



Habitat Portum Sanctum (hinc inde in montibus vulgaris), 

 necnon Desertam Grrandem Desertamque Australem (rarissima). 



The L. gracilis was considered by Mr. Lowe to include 

 three well-marked phases, namely the ' var. vitrea ' (which is 

 small, thin, extremely glossy and hyaline, and which, from its 

 being the state which was originally described and figured by 

 him as the ' Achatina gracilis," 1 must be regarded as the typical 

 one 1 ) ; the 'var. subula' (which is larger and more elongate, 

 thicker in substance, less shining in surface, less transparent, 

 and somewhat yellower in hue) ; and the * var. terebella ' (which 

 is altogether larger still, and more ventricose and convex, and 

 has its aperture a trifle longer, wider, and more outwardly- 

 rounded and developed). But, after much consideration, I arn 

 inclined to think that it will be more natural to regard at any 

 rate the ' var. vitrea ' as specifically distinct, in which case it 

 alone will represent Mr. Lowe's Achatina gracilis. And this 

 is all the more desirable, inasmuch as that particular form is 

 not merely Porto-San tan (like the subula and terebella), but 

 one which occurs likewise on the Desertas, it having been 

 taken on the Deserta Grande by myself, and obtained from 

 the Southern Deserta by the Baron Paiva. 



As thus limited, therefore, the L. gracilis may be known by 

 its small size and somewhat slender outline, by its extremel) 



1 Although this is mentioned expressly by Mr. Lowe in his ' Synopsis 

 Diagnostica,' I am likewise able to corroborate it from my own observation, 

 inasmuch as I possess the two original examples from which his figure (in 

 the ' Transactions of the Cambridge Philosophical Society') was taken. 



