INTRODUCTION. 



The Primates, which is the first of the Linnaean Orders of the 

 Mammalia, was originally composed of four genera Homo, Simia, 

 Lemur and Vespertilio, Man, Monkeys, Lemurs and Bats. The last 

 has been dropped by general consent, and the Order as now con- 

 stituted combines the Bimana and Quadrumana. 



Some Naturalists have contended that the Lemurs should be 

 placed in a separate Order, and my friend the late Prof. A. Milne- 

 Edwards enumerates the following characters as justifying this view: 

 The bell-shaped, diffused and non-deciduate placenta, vast size of the 

 allantois, uncovered condition of the cerebellum, cranial structure, 

 inferior incisors, and structure of the extremities, (developed pollux, 

 and discoidal terminations of the fingers). 



While admitting the importance of these characters, *St. George 

 Mivart has made some critical remarks regarding the decision of Prof. 

 A. Milne-Edwards, and fairly well establishes the fact that the better 

 course would be to leave the Lemuroidea as a Suborder of the Pri- 

 mates as "there can be no doubt that Man- Apes, (including Baboons 

 and Monkeys), and Half- Apes together constitute a group capable of 

 convenient and very distinct Zoological definition," and he defines the 

 group as follows : "Unguiculate, claviculate placental mammals, with 

 orbits encircled by bone; three kinds of teeth, at least at one time of 

 life; brain always with a posterior lobe and calcarine -fissure; the inner- 

 most digits of at least one pair of extremities opposable; hallux with 

 a Hat nail or none; a well-developed caecum; penis pendulous ; testes 

 scrotal; always two pectoral mammce." 



The Order Primates then comprises two Suborders Lemuroidea 

 and Anthropoidea. The first contains the singular nocturnal animals 

 known as Lemurs which are distinguished from the members of the 

 other Suborder by the following characters: 



Orbit opening into the temporal fossa beneath the postorbital 

 bar, (Tarsius excepted). The lachrymal foramen situated outside the 

 orbital margin. The second digit of the hand may be merely a rudi- 

 ment, but the same digit of the foot has a long pointed claw. The 

 cerebrum does not overlap the cerebellum, and the hemispheres have 



♦Proc. Zool. Soc. Lond., 1873, p. 504. 



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