82 TESTACEA ATLANTICA. 



Habitat Maderam (vulgatiss.), Desertam Grandem (rarior), 

 et Desertam australem (rariss.); hinc inde, in intermediis, sub 

 lapidibus. In statu semifossili in Madera propria ad Canical 

 abundat; necnon in summo etiam Desertse Australis semi- 

 fossilis exstat, sed ibidem rarior. 



This is one of the most universal, and characteristic, of the 

 Land Mollusca of Madeira proper, and one which occurs like- 

 wise, though more rarely, on the Desertas : but in Porto Santo 

 it seems to be absolutely non-existent, there being no traces 

 of it in either a recent or a subfossil condition. In Madeira 

 proper however it is extremely abundant, principally at inter- 

 mediate but also at comparatively low elevations, frequently 

 swarming (as on the lofty sea-cliffs towards the Cabo Garajao, 

 or Brazen Head) amongst loose stones and rubbish, as well as 

 amongst the soil around the roots of shrubby plants. On the 

 Northern Deserta (or Ilheo Chao) it has not yet been observed, 

 though we may expect that it will sooner or later be found 

 there ; but on the Deserta Grande it is not very uncommon, 

 although by no means abundant ; whilst on the Southern De- 

 serta, where it was met with by Mr. Lowe, and from whence it 

 has been obtained subsequently by the Baron Paiva, it is ex- 

 tremely rare. 



In a subfossil state the P. bifrons teems in the calcareous 

 and muddy deposits at Canipal ; and it likewise exists, though 

 much more sparingly, on the summit of the Southern Deserta. 



The P. bifrons (which is rather variable in stature, adult 

 specimens ranging from about 5 to 8 lines across the broadest 

 part) may be known by its rather flattened, discoidal contour, 

 pale corneous-yellow hue (often with a faint greenish tinge), 

 and by the oblique and curved costse with which its very nume- 

 rous volutions are roughened. Its underside is shining and 

 free from ridges (it being merely sculptured with radiating 

 lines) ; its umbilicus is deep, but not large ; the region about 

 (or immediately before) its aperture is usually of a more de- 

 cided yellow; and its apical whorls are for the most part 

 whitish or decorticated. 



Patula stephanophora. 



Helix stephanophora, Desk., in Fer. Hist. 111. t. 90. f. 8. 

 calathus, Lowe, Ann. Nat. Hist. ix. (1852) 

 stephanophora, Pfeiff., Mon. Hel. iii. 142 (1853) 

 calathus, Lowe, Proc. Zool. Soc. Loud. 178 (1854) 

 stephanophora, Alb., Mai. Mad. 44. t. 11. f. 17-20 



(1854) 

 calathus, Paiva, Mon. Moll. Mad. 25 (1867) 



