FAUNAE VARIATION. 3 



On the other hand, a journey of only very moderate duration 

 will frequently disclose the greatest diversity existing between con- 

 tiguous faunas. The traveller who starts east from the African 

 coast, and who has familiarised himself with the strange produc- 

 tions of the African continent, its elephants, giraffes, rhinoceroses, 

 hippopotami, lions, and antelopes, finds none of these in the island 

 of Madagascar ; the true monkeys have also disappeared, and in 

 their place he meets with forms of half -monkeys (lemurs), a group 

 of animals with which he will have already become acquainted 

 before leaving the mainland. Strange creatures, wholly unlike 

 anything previously known to him, now arrest his attention, and 

 he finds himself in the midst of. what might be termed a peculiar 

 fauna. Likewise, if he leave the shores of Central America or 

 Florida for the Great Antilles, the same marked isolation of the 

 new fauna manifests itself. The larger forms of quadrupeds, such 

 as the jaguar, couguar, tapir, and peccary, are wholly wanting, 

 and even among the smaller and more numerously represented 

 mammalian types many of the more prominent forms will be sought 

 for in vain. On the other hand, he will make the acquaintance of 

 entirely new groups of animals, some of which, like the Centetida?, 

 have their nearest foreign representatives in regions removed by 

 nearly one-half the circumference of the globe. And this diversity 

 in the faunal type is found to permeate to a greater or less extent 

 all the individual groups, birds, reptiles, &c., of the animal king- 

 dom. 



It might be rashly supposed that the distance separating the 

 regions under comparison would sufficiently account for the pecu- 

 liarities of their respective faunas, or the disparities separating 

 them; but distance alone, without a special relation binding to- 

 gether the principals between which it is supposed to act, can 

 effect nothing. We have, indeed, seen upon what a vast extent 

 of territory the British faunal facies is stamped, and were any 

 further proof needed of the inefficacy of distance, pure and simple, 

 as a prime factor in geographical distribution, we have but to 

 transport ourselves to the Malay Archipelago, and observe how 

 wonderfully diverse are the respective faunas on either side of the 

 very narrow (but deep) channel separating the islands of Bali and 

 Lombok from each other. 



Mysterious as these various phenomena of distribution may ap- 



