CHAP. Ill] THE MAMMALIAN ORDER PRIMATES 59 



Hallux not opposable. 



Pelvic limbs much longer and bulkier than the pectoral. 



Cerebral hemispheres enormously developed in bulk and in 

 the complexity of the convolutions. 



Many morphological modifications have been induced by the 

 assumption of the erect attitude. 



This family includes members of the two Human species. 



It is a matter for discussion whether there should be inter- 

 polated between the Families Simiidae and Hominidae another, 

 viz. Pithecanthropidae. Till further remains of Pithecanthropidae 

 have come to light this question must remain in abeyance. Some 

 authors would rank Pithecanthropus erectus with the Simiidae, 

 and others again associate this form with the Hominidae. 



In concluding the account of the Order Primates, a few words may be 

 added as to the method pursued in assigning to Man a place among the 

 Mammals. It will have already been noticed that in the account given of the 

 Order Primates, several morphological characters were enumerated. Should 

 a mammal be presented for examination with a view to assigning it to its 

 appropriate order, it would be necessary that the mammal should satisfy the 

 conditions just referred to, before such assignation could be made in respect 

 of the Order Primates. But the exact number of conditions is a matter upon 

 which no final decision has been arrived at. It is conceded very generally 

 that the decision should not depend on a single character. And however 

 desirable it may seem, to limit the number of tests for the sake of convenience 

 and lucidity, no hard-and-fast rule (as to the precise number of tests) can be 

 formulated. An example of the procedure may facilitate this explanation. 

 We may for instance consider the morphology of a typical Primate mammal 

 and enumerate a dozen characters in which it presents the requisite con- 

 formation. The corresponding list for the human body would shew that 

 the same conditions were satisfied in this as in the preceding case. Closely 

 similar results would follow the application of the test to the various 

 animals just mentioned, and it is in this way that the constitution of the 

 Order Primates has been effected. Nevertheless, difficult cases occur, and 

 one of these has been selected by way of illustration. Should we be confronted 

 by such a form of mammal as Galeopithecus volans (which was included 

 among the Primates at an epoch when the single character of the possession 

 of two incisor teeth in each jaw was regarded as the sole qualifying condition), 

 we should see but small reason at first for regarding it as outside the limits of 

 that Order. 



The comparison may be drawn up as follows, the selected characters 

 including nine of the most important of those already employed (in the 

 general diagnosis of the Primates, cf. p. 44 supra). 



