Prof. A. Mousson on the Molluscan Fauna of the Canaries. 87 



cies was discovered by MM. Webb and Berthelot on both the 

 islands from which it has been brought by Herr Hartung. In 

 some examples the aperture is quite horizontal at the base of the 

 shell, and has a flat reflected rim more than a line broad. 



9. Bulimus decoUatus, Brug. Not to be distinguished from 

 the European form. The whole of the individuals, as well as 

 most of those of H. sarcostoma, and several of H. pisana Albo- 

 ranensis, are in a white, chalky condition, which might be called 

 semifossil ; but this appears not to be so much an efiect of age 

 as of the habitat in hot sea-sand. 



Of the nine species collected by Herr Hartung, one. Helix 

 fft-anostriata, is therefore quite new ; H. pisana geminata, H. im~ 

 pugnata, H. monilifera, H. Despreauxii moderata, H. sarcostoma, 

 although long known, appear peculiar to the two islands ; only H. 

 persimilis and pisana Alboranensis are also enumerated in other 

 islands, whilst B. decoUatus is common to the whole of the coun- 

 tries on the IMediterranean. From these results, one may hope 

 for further discoveries when Herr Hartung carries out his pur- 

 pose of another visit to both these islands, and of the exploration 

 of others of the less-known Canary Islands. Not till the com- 

 pletion of our knowledge will it be possible to lay down, com- 

 prehensively and conformably to nature, the peculiarities of the 

 Molluscan fauna of the Canaries, and its interesting relations to 

 those, on one side, of the coasts of Europe and Africa, on the 

 other, of the rest of the Atlantic archipelagos. I confine myself 

 for the present to a few remarks. 



In position, climate, volcanic soil, and vegetation, the Canaries 

 approach very near to the Madeiran group. It is the more 

 extraordinary to find the Molluscan fauna remarkably diff"erent 

 and more nearly related to that of the continental shores of the 

 IMediterranean. With the exception of a set of species {Helix 

 cellaria, lenticula, pisana, aspersa, lactea, Bui. decoUatus) which 

 follow the shores of the Mediterranean from the east as far as 

 Portugal, the Canaries and Madeira actually possess besides 

 H. pauper cula, not a single species in common, — at least none 

 which does not also belong to the continent. All preceding 

 statements (e. g. H. tiarella) rest on uncertain determinations or 

 incorrect habitats. ]Moreover, even the predominant types on 

 both these groups of islands are dififerent ; so that those very 

 types which are developed in the richest variety on the one are 

 scarcely or almost not at all represented on the other by single 

 detached species. 



Thus in Madeira and Porto Santo the following types form 

 the basis of the Helix-iv'iht : — 



(1.) The section Ochthephila of Beck, which Dr. Albers has 



