4 TEST ACE A ATLANTIC A. 



exceptionally developed in the Madeiran group and which is 

 present also, thongh more sparingly, at the Canaries, is a tact 

 which should particularly be noticed ; as well as the occurrence 

 at the Azores and Canaries of the Bulimus variatus, W. et B., 

 and of that singular little species the Hydroccena gutta, — 

 which, of all the members of the .Gastropoda, is perhaps the 

 least likely to have been accidentally naturalized. As for the 

 Auricidida^, which seem to be much the same in the three 

 archipelagos, I lay but little stress upon them, — for those 

 littoral forms, which in their Tnodus vivendi are practically 

 marine, have almost everywhere a wide geograpliical range. 



These few instances, however, of course do not embody all 

 that the archipelagos have in common, — for they are principally 

 ' Atlantic ' forms, from which the strictly European element has 

 been eliminated. If we take the actual species into account 

 which the Azores (even as hitherto imperfectly known) would 

 appear to possess conjointly with the more southern groups, we 

 shall tind that there are about 26. which occur equally in the 

 Azores and Madeiras, and about 1 9 in the Azores and Canaries ; 

 which (taking the European element for what it is worth) 

 undoubtedly shows an amount of affinity between the three 

 archipelagos which cannot well be ignored. The Eev. H. B. 

 Tristram, in his accoimt of the Pulmoniferous Grastropods of the 

 Azores, published in Mr. Grodman's volume, can scarcely have 

 had very reliable data to draw upon in instituting his compari- 

 son between the Azorean fauna and those of the two archipelagos 

 the next in succession to the south of it, — for he asserts that it 

 has only 7 species in common with the Madeiras, and 4 with 

 the Canaries ; whereas, according to my computation, it pos- 

 sesses (as just stated) at least 26 in common with the Madeiras, 

 and 1 9 with the Canaries ! ^ Or, if we regard the Madeiras and 

 Canaries as integral portions of a single ' Atlantic province,' no 

 less than 31 species out of the 71 of which the Azorean fauna is 

 made up permeate more or less of the latter, — 5 of them ranging 

 even to the Cape Verdes, and 5 to St. Helena.^ 



' The 26 species which are found equally in the Azores and Madeiras are 

 these: — Arion ater, Limax ciagates, maiimiis, Jfarits, and agrestis, Testacella 

 Maugti, Hyalina cellaria and crydallina, Putvla rotundata and jjiisilla, Helix 

 jnilchella, eruheHcens, aspersa, jnsana, armillata, iiaupercula and lenticula, 

 Bulimus fentrieosus, Stenogyra deeollaia, Acltatina luhrica, JBalea jjeiTersa, 

 Pupa microspora and anconogtoma, Aui-icuM cpqualis and vespeHina, and 

 Pcdipcs ufru : whilst the following 19 are those which are common to the 

 Azores and Canaries: — TcstaccUa Maugci, Hyalina cellana and crystallina, 

 Patula jJvsilla, Helix pulcliella, aspersa, lactca, pisuna, opicina, panpercxda, 

 and lenticula, Bulimus ventricosus and variatus, Stenogyra decollata, Pupa 

 microspora and aucunostoma, auricula cequalis and bicolm; and Hydroccena 

 gutta. 



- Mr. Tristram says, likewise, that 'It should be observed that, of all the 

 Pulmonifera of the Azores, Pedipes afer is the only one common to the 



