60 TEST ACE A ATLANTIC A. 



more pronounced forms to which the name * species ' must prac- 

 tically be given. 



Marvellous however as is the segregation of the various 

 forms in the Madeiran Group which are truly indigenous, — only 

 about seven actual species (apart from the littoral, subsaline 

 ones, which in their modes of life are practically marine) having 

 apparently been either transmitted to or received from the 

 neighbouring archipelagos, and only about five having been ob- 

 served as yet on all the islands of the cluster,— I would by no 

 means wisla to insinuate that a certain unmistakeable relationship 

 is not plainly indicated between some of the members of certain 

 well-marked types which permeate more or less of the entire 

 * province' Thus, for instance, the Helicideous section Leptaxis, 

 which is so characteristic of the Madeiras, may be said, although 

 totally absent from the Canaries, to be the dominant one both 

 in the Azores and Cape Verdes ; the section Discula, which is so 

 abundant and universal at the Madeiras, but which is non-exis- 

 tent at the Azores, puts in an appearance (even though, in com- 

 parison, feebly) at the Canaries ; the Vitrinas and Pupoi are 

 largely developed, and under somewhat analogous modifications, 

 in tlie three northern Grroups ; the Bulinii, although totally un- 

 represented (except under a couple of exponents which have 

 manifestly been introduced) at the Madeiras, are expressed to a 

 monstrous extent both at the Azores and the Canaries ; the ge- 

 nus Lovea (allied to Achatina, and lately enunciated by Mr. 

 Watson) reigns supreme in the Madeiran and Canarian archi- 

 pelagos, but is ivanting at the Azores and Cape Verdes ; the 

 Cyclostomideous Craspedoponia, which attains its maximum in 

 Madeira, extends into both the Azorean and Canarian Groups ; 

 and the minute HydoccBna gutta crops up at the Azores and 

 Canaries, but is absent from Madeira. From which it will be 

 seen, without adducing further instances, that many of the most 

 distinctive types range over mo7'e or less of these immediate 

 archipelagos, — being sometimes absent from one of them and 

 sometimes from another, but combining as a lohole to give a 

 certain amount of unity to what we may be permitted to call 

 this ' Atlantic region.' 



In the preceding remarks I have endeavoured to show that 

 in the actual species of which its fauna is composed the Madei- 

 ran Group is almost wholly independent of the others which are 

 to the north and south of it, but at the same time that a consi- 

 able proportion of characteristic types which permeate to a 

 greater or less extent the whole of the archiiDelagos impart 

 nevertheless a certain individuality to the entire province which 

 cannot well be ignored. This general connection of the clusters, 



