88 ORIGIN AND CLASSIFICATION 



Carnivora. As no other order can claim the family Galeopithecidce, 

 it is placed here, but rather for convenience than for any other 

 consideration, since it has but little if any relationship with any of 

 the other members. Its isolated position is indicated by assigning 

 it a distinct subordinal rank. 



The Chiroptera have always been placed near the Insectivora ; 

 but they are really a highly specialised group, as much isolated 

 from all other mammals by the modification of their anterior limbs 

 in adaptation to aerial locomotion, as the Cetacea and the Sirenia, 

 by the absence of hind limbs, are specially adapted for an aquatic 

 life. 



Lastly, the Primates, which in any natural system must be 

 placed at the head of the series, are divisible into two very distinct 

 groups — one containing the various forms of Lemurs (Lemuroidea), 

 and the other the Monkeys and Man (Anthropoidea). Whether 

 the Lemuroidea should form part of the Primates (according to the 

 traditional view), or a distinct order altogether removed from it, 

 is as yet an undetermined question, for both sides of which there 

 is much to be said. There can, however, be no doubt that the 

 Anthropoidea form a perfectly natural group, presenting a series 

 of tolerably regular gradations from the Marmosets {Hapxdc) to 

 Man. Certain breaks in the series, however, enable us to divide 

 it into five distinct families : — Hapalida' or Marmosets ; Cebiclce or 

 American Monkeys, with three premolar teeth on each side of each 

 jaw ; Cercopithecidce, containing the majority of Old-world Monkeys ; 

 Simiidce, consisting of the genera Hylobates, Simia, Gorilla, and 

 Anthropopithecus, the true Man -like Apes; and, lastly, LTominida; 

 containing the genus Homo alone. 



Subclass I. Prototheria. 

 Order i. Monotremata — Monotremes. 



Fam. 1. OrnithorhynchidcB — Duck-bill. 

 2. Echidnidce — Spiny Anteater. 



Group. MULTITUBERCULATA. 1 



Fam. 1. Plagiaulacidse — Plagiaulax. 



2. Polymastodontidae — Polymastodon. 



3. Tritylodontidse — Tritylodon. 



Subclass II. Metatheria. 

 Order ii. Marsupialia — Marsupials. 



Suborder 1. Polyprotodontia — Polyprotodonts. 



1 The names of the groups containing only extinct forms are printed in heavier 

 type than those which contain species still existing. 



