534 CHARACTERS OF PRIMATES CHAP. 



group to which so many others appear to converge. It is dis- 

 puted, for example, whether the Chriacidae among extinct Lemurs 

 are rightly placed, or whether they should be referred to the 

 Creodonta. The number of primitive characters seen among the 

 Primates, even in Man himself, is remarkable. Of these the more 

 important are the five digits of both limbs and the plantigrade 

 walk, the presence of clavicles and of a centrale, and the absence 

 of a third trochanter. All these features distinguish the early 

 Eutheria. 



SUB-ORDER 1. LEMUKOIDEA. 1 



The animals known as Lemurs, from their nocturnal and ghostly 

 habits, are on a lower level of organisation than the other division 

 of the Primates. Even the external form enables the members 

 of the present sub-order to be readily distinguished from the 

 higher Anthropoidea. The head is more like that of a Fox, with 

 a sharp muzzle ; it lacks the human expression of the face of even 

 the lower among the Apes. The long tail is never prehensile, and 

 there is never any trace of cheek pouches or of integumental 

 callosities, which are frequently so characteristic of the Apes. 

 The Lemurs agree with the remainder of the Primates in having 

 pectoral mammae (sometimes abdominal ones are present in 

 addition, and in Hapalemur in the male at least there is a 

 mamma upon each shoulder), in having opposable thumbs and 

 toes, and in the flattened digits. The tail varies from complete 

 absence (in the Loris) to a great length and bushiness in 

 the Aye -aye. The pectoral limbs are always shorter than 

 the hind -limbs; the reverse is occasionally the case in the 

 Anthropoidea. A curious contrast between the two divisions 

 of the Primates concerns the digits of the hands and feet. In 

 the Anthropoidea it is the hallux or pollex which is subject to 

 great variation. In the Lemurs, on the contrary, the thumb 

 and great toe are always well developed, but the second or 

 the third digit constantly shows some abnormality; thus the 

 singular elongation of the third digit of the hand in CMromys 

 and the absence of the index in the Potto. 2 In all Lemurs the 



1 See Dr. Mivart's papers in Proc. Zool. Soc. 1864, -65, -66, -67, and -73 foi 

 osteology and teeth. 



2 Murie and Mivart, Trans. Zool. Soc. vii. 1869, p. 1. 



