82 TEST ACE A ATLANTIC A. 



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



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



lapidibus. In statu semifossili in Madera propria ad Canical 



abundat; necnon in summo etiam Deserta? 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 

 N< >rthern 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 Canical ; 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 costas 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. Lond. 178 (1854) 

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



(1854) 

 „ calathus, Paiva, Man. Moll. Mad. 25 (1867) 



