88 Prof. A. Mousson on the Molluscan Fauna of the Canaries. 



divided into the groups Tectula, Ochthephila, and Actinella, and to 

 which belong, e. g., H. turricula, Maderensis, arcta, polymorpha, 

 Bulweriana, &c., comprehends in the Madeiran graup not less 

 than thirty-three species. In the Canaries, H. taniata, Webb, 

 alone bears the distinctive features of the type ; this species is, 

 however, doubtful, not having been collected on the spot, but 

 found in bales of orchil not known to have come from any nearer 

 place (D'Orb. l. c, p. 63)*. 



(2.) The groups Leptaxis and Plebecula of Lowe, which are 

 related to the species erubescens, punctulata, and undata, Lowe, 

 and comprehend about fourteen species. The only Canarian shell 

 approaching to this type is H. advena of Webb (D^Orb. p. 58), 

 which, indeed, is directly called by Dr. Albers (Malac. Maderens. 

 p. 49) a Porto- Santan species. If, however, the authentic form 

 of Mr. Webb's species (D'Orb. t. 1. f. 18-20) be compared 

 with the figure which Dr. Albers (t. 2. f. 26, 27) gives of the 

 Porto-Santan shell, they can hardly be considered as identical f. 



(3.) The division Campylaea, existing in three forms, partly 

 living, partly subfossil, in the Madeiras, possesses in the Cana- 

 ries not one single genuine representative; for the somewhat 

 allied H. Villiersi, D'Orb., must rather be considered as an oscu- 

 lant form of the type plicaria. 



(4.) In Madeira we find a set of Clausilia, all peculiar, but 

 still the precursors of this very abundant European genus. In 

 the Canaries, neither the researches of MM. Webb and Berthelot, 

 nor the exhaustive discoveries in Teneriffe of Herr Blauner, have 

 brought to light so nmch as a single species. 



* H. tceniata, Webb, by examination of D'Orbigny's original types, proves 

 to be merely a large state of H. Maderensis, Wood, which is one of the very 

 commonest Madeiran species, but which has not hitherto been found in 

 any of the other islands of even the Madeiran group, and certainly not in 

 any one of the Canaries. — Tr. 



t H. advena, Webb, by the original tyi)es in D'Orbigny's Canarian 

 collection, is identical with the Madeiran (North and Great Dezertan) form 

 {sdtx.y.) of H. erubescens, \jO\yQ. The Porto-Santan shell, described and 

 figiu-ed by Dr. Albers, loc. cit., is another different or distinct form of the 

 same species, found also by Mr. WoUaston and myself, in 1855, on the 

 summit of Pico do Facho in Porto Santo. No form of this species has 

 been ever really found in the Canaries ; and there can be no reasonable 

 doubt that the orchil which produced H. advena, Webb, like that in which 

 H. tceniata, Webb, is said to have occurred, was of Madeiran or Dezertan 

 origin — if both these shells, indeed, may not be supposed to have been 

 collected in Madeira by Webb himself in 1828-9, and to have become 

 afterwards mixed up by accident with Terver's orchil-species. 



At all events, the two conclusions founded, in the text, on the supposed 

 Canarian origin of H. taniata and advena, retpiire better substantiation ; 

 and Ochthephila, Beck, with Leptaxis and Plebecula, Lowe, still remain, 

 equally witl) Canipiflferi, Beck, without any genuine or certain Canarian 

 representatives.— Tr. 



