148 TEST ACE A ATLANTIC A. 



cuous ; and its whorls (which are only 5 or 5^ in number) are 

 flattened on the spire (the nucleus of which is, nevertheless, rather 

 prominent), and very densely crowded with sharply defined, but 

 minute, transverse lines, which on the ultimate and penultimate 

 volutions are minutelv sub-undulated, — a certain number of 

 them, moreover, being irregularly raised (along a 'portion of 

 their length) into short lamelliform ridges (much resembling 

 those of a file), which last are developed on the underside and 

 about the region of the keel into longer hook-shaped hairs or 

 filaments, and generally enlarged along the keel (when the 

 specimens are fresh and unrubbed) into ray-like processes. The 

 margins of its peristome are wide apart at their insertion, but 

 connected by a very thin corneous plate; and its basal whorl 

 descends but very slightly, and for only a very short distance, 

 in front. 



(§ Caracollina, Beck.) 



Helix lenticula. 



Helix lenticula, Fer., Tail. Syst. 37. 154 (1821) 



„ subtilis, Loive, Cam.br. Phil. S. Trans, iv. 45. t. 5. 



f. 13 (1831) 

 „ lenticula, d'Orb., in W. et B. Hist. 66. t. 2. f. 10-12 

 (1839) 

 Pfeiff., Mon. Hel. i. 211 (1848) 

 „ „ Lowe,Proc. Zool. Soe. Lond. 196 (1854) 



„ ,, Alb., Mai. Mad. 43. t. 11. f. 9-12 (1854) 



„ „ Paiva, Mon. Moll. Mad. 96 (1867) 



„ „ Dohrn., Mai. Bldtt. xvi. 3 (1869) 



„ „ Mouss., Faun. Mai. des Can. 66 (1872) 



,, „ Watson, Journ. de Conch. 222 (1876) 



Habitat Maderam, et Portum Sanctum; in aridis apricis 

 inferioribus, praeeipue cultis, parce degens. 



The common Mediterranean H. lenticula — so easily recognized 

 by its flattened, strongly carinated form, its rather large and spiral 

 umbilicus, its bald, opake, finely striated surface, and its corneous- 

 brown hue — occurs sparingly both in Madeira and Porto Santo 

 (in the latter of which it was first obtained by myself in 1849), 

 at low elevations and in more or less cultivated spots. In 

 Madeira proper it was originally detected, during May of 1827, 

 about the Piedade chapel (above the fossil-bed) on the Ponta de 

 Sao Lourenco, by Mr. Lowe, — who likewise met with it, early 

 in the following year, at the Praia Bay. By myself and others 

 it has more often been taken around Funchal, — where it is fre- 

 quently found about old walls, and beneath stones in dry places 

 amongst the Opuntia Tuna, or Prickly Pear. In the first 

 ravine (and on the adjoining cliffs) to the eastward of Funchal, 



