304 TEST ACE A ATLANTIC A. 



are indicated at the latter ; though, on the other hand, I am 

 willing to admit that the southern archipelago has been so 

 much less fully investigated than the more northern one that 

 some allowance must unquestionably be made on that account, 

 even whilst my own experience in them both would incline 

 me to believe that the Madeiras, in proportion to their superfi- 

 cial area, will be found, even eventually, to be far more com- 

 pletely gorged with aboriginal types (and types, I may add, of 

 a more isolated and peculiar character) than the Canaries. 



It is indeed a rather puzzling fact, but one which is borne 

 out equally by the Coleopterous statistics, that, despite their 

 more southern position, the Canaries have nevertheless a far 

 more decided Mediterranean and north- African element about 

 them than what we observe in the Madeiran Group. Take, for 

 instance, the distinctively Canarian Helix lancer ottensis, which 

 "is found in the whole seven islands of the archipelago, but which 

 also ranges up the western coast of Morocco, or the no less 

 essentially Canarian H. argonautula, which has recently been 

 detected (under a scarcely altered phasis) further in the interior 

 on the opposite mainland ; or take the Helicideous department 

 Hemicycla, and the genera Parmacella, Leucochroa, and 

 Cyclostoma, which are not represented in even any of the other 

 archipelagos, but the first of which (replaced at the Madeiras, 

 Azores, and Cape Verdes by Leptaxis) numbers thirty-seven 

 members (indeed probably more), whilst the fourth, although 

 not numerous in species, has separate modifications for nearly 

 every island of the Canarian cluster. The genus Bulimus, too, 

 which has fully thirty exponents in the Canaries, is absolutely 

 unknown at the Madeiras except as embodied by the common 

 B. ventricosus, which has simply been introduced. Then, at 

 the Canaries, we meet with, also, none of the more anomalous 

 and isolated types such as the Helix delphinula, the members 

 of the sections Coronaria, Tectula, Hystricella, Helicomela, 

 Placentula, and Katostoma, and the Pupa cassida which are 

 so conspicuous in the Madeiran archipelago ; though, on the 

 other hand, it must be confessed that the European and other- 

 wise widely-spread genus Clausilia, which is universal at the 

 Madeiras, is without a representative not only at the Canaries, 

 but in every other island of the ' Atlantic province.' 



Yet although the Canarian and Madeiran Groups are thus 

 conspicuously disconnected as regards their Gastropodous fauna 

 (only seven species, when the cosmopolitan and manifestly intro- 

 duced ones have been removed, being common to them both ] ), 



1 These seven truly * Atlantic ' Gastropods which are common to the 

 Canaries and the Madeiras (after the merely naturalized and cosmopolitan 

 ones have been deducted) are as follows : the Patula i)landa, Shuttlw., and 



