210 TEST ACE A ATLANTIC A. 



cumstances precisely similar to those at Madeira, namely from 

 amongst lichen on the trunks of trees in the lofty wood of Las 

 Mercedas, as well as in the damp sylvan region above Taganana, 

 and near Ycod-el-Alto, of the former ; and at a high elevation 

 in the Barranco da Agua, and on the ascent of the Cumbre 

 above Buenavista, of the latter. My Canarian examples were 

 overhauled with great care by Mousson, who agreed with me in 

 regarding them as the exponents of a Pupa which is certainly 

 distinct from Mr. Lowe's P. anconostoma ; but as I had not at 

 that time identified them with the Madeiran P. fanalensis, he 

 enunciated the species afresh, in his recent Monograph, under 

 the name of P. debilis, adding, as a subsequent remark, ' Les 

 differences constantes de cette forme d'avec la P. anconostoma, 

 Lowe, me semblent en justifier la separation. La P. debilis, 

 dont j'ai compare un bon nombre d'individus est toujours plus 

 petite, plus fragile, oviforme et non cylindracee ; le dernier tour 

 pres de la rime n'est pas comprime, mais arrondi ; 1'ouverture 

 est relativement plus largement arrondie, et pourvue d'un peri- 

 stome a peine reflechi ; la paroi ne presente qu'une faible dent 

 qui souvent manque entierement. Les deux especes sont a peu 

 pres dans le meme rapport que le P. Semproni, Charp,, a Yum- 

 bilicata, Drap.' 



After a very accurate comparison, I have no doubt concern- 

 ing the specific identity of Mousson's Canarian species with the 

 Madeiran one, both of which moreover pass through the same 

 amount of, rather considerable, variation. 



Judging from my own observations, and from the numerous 

 types which are now before me, the P. fanalensis may be said 

 to differ from the var. ft. anconostoma of the P. umbilicata in 

 being on the average very much smaller and more globose, or 

 ventricose ; in its substance being thinner, and its surface more 

 white and decorticated (much as in the P. limnceana) ; in the 

 number of its volutions being usually one less ; in its aperture 

 being generally a little shorter and rounder ; and in the obsolete 

 indications of a rudimentary plait on the columella which are 

 for the most part just traceable in its ally being quite absent. 



Pupa umbilicata, 



Pupa umbilicata, Drap., Tabl. des Moll. 58 (1801) 



Helix anconostoma, Lowe, Cambr. Phil. S. Trans, iv. 62. 



t. 6. f. 30(1831) 



Pupa anconostoma, Pfeiff., Mon. Hel. ii. 314 (1848) 

 Lowe, Proc. Zool. Soc. Lond. 208 (1854) 



Alb., Mai. Mad. 61. t. 15. f. 19-22 



(1854) 

 Morel., Hist. Nat. des Acor. 198 (1860) 



