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



(4.) The species cyclodon, Webb, Despreauxii, D'Orb., mode- 

 rata, MSS., argonautula, Webb, yranostriata, MSS., have no 

 kindred forms in the Madeiras*. On the other hand, they unite 

 — aSj however^ well-distinguished forms — with certain S. Euro- 

 pean types. 



(5.) The same may be said of the horny-shelled H. diaphana, 

 Lam., afficta, Fer., fortunata and discobolus, Shutt., hispidula, 

 Lam. With the exception of the universally diffused H. lenticula, 

 Fer., nothing similar occurs in Madeira f. On the other hand, 

 the S. European H. lens and ciliata are more nearly related. 



(6.) In Bulimus, the extensive groups of obesatus and variatus, 

 Webb, uniting with the European B. montanus and obscurus, 

 are quite wanting in Madeira and Porto Santo. Strange to say, 

 however, they again lind, though indeed in a remarkably aber- 

 rant form {B. eganeus, Alb.), a representative in the Azores. 



(7.) Cijclostoma lavigatum, Webb, belongs to the type of the 

 European C. eleyans, also occurring in the Canaries j, but not 

 mentioned as a Madeiran species. 



These few observations may suffice to indicate the natm'e of 

 the Canarian famia in comparison with both the S. European 

 and Madeiran, as also its far greater affinity with the first than 

 with the last. To complete more perfectly its characterization 

 and comparison, additions are still wanting to our information 

 in three dn-ections : 1st, with respect to the species of the less- 

 visited islands ; for, excepting Teneriffe and Palma, not one can 

 really be considered as exhaustively explored ; 2ndly, with refer- 

 ence to the Molluscan fauna of the Cape de Verdes, which, con- 

 sidering then- position over against the continent, should have 

 the nearest resemblance to the Canaries, though their more 



Canarian) H. Michaudi, Desh., is a genuine, nay, typical species of the 

 same group, viz. Lemniscia, Lowe. — Tr. 



* H. argonautula, Webb, certainly, and H. granostriata probably, be- 

 long to the peculiarly Madeiran group Discula. H. cyclodon, Webb, is of 

 extremely doubtful origin as to habitat, and it is probably as little entitled 

 to a place in the Canarian as in the ^ladeiran fauna. The assertion in the 

 text, therefore, relatively to the Madeiras can be fully admitted only in the 

 case of H. Despreauxii, D'Orb., of which moderata is merelv a variety, and 

 which, hke H. cyclodon, D'Orb., belongs to the restricted group Crenea, 

 Alb., typified by H. elegans, Drap., — a group of which Madeira certainly 

 possesses no true representative. — Tr. 



t It may be doubted whether all the species above enumerated belong 

 really to the same group; and some will perhaps prove to have their 

 genuine counterparts in Madeua. — Tr. 



X Whether C. Icevigatum, Webb, be really distinct from C. elegans 

 (Miill.), seems veiy questionable. Certainly one species only of this tvpe 

 has ofiFered itself to the combined researches of myself and Mr. Wollaston 

 in any of the seven Canarian islands. In the Madeiran nothing of the sort 

 occurs. — Tr. 



