EXTINCT FORMS. 653 



feed on the juices of the sugar-cane, etc., on fruit, and on wood-boring 

 caterpillars which it gets at with its rodent-like incisors, and then picks 

 out with its thin finger, but the use of the latter is not clear ; nocturnal 

 and difficult to observe, makes a nest in trees. Dentition ic%pml; 

 incisors large, rodent-like, with enamel on front only, with persistent 

 pulps ; grinding teeth with flat, faintly tuberculated crowns ; milk 

 dentition i \ c m f . One genus and species, Chiromys madagascar- 

 ensis, the aye-aye, Madagascar. 



A large number of extinct lemurs are known from the Eocene of Europe 

 and N. America, but their remains have not been found, with the excep- 

 tion of one or two species in the Lower Miocene, in the formations inter- 

 vening between the Eocene and the Pleistocene. The following may 

 be mentioned, Anaptomorphus Cope, Omomys Leidy, Mixodectes Cope, 

 Necrolemur Filhol, Microchoerus Wood, Adapis G. Cuv., Caenopithecus 

 Rut., Pelycodus Cope, Hyopsodus Leidy, Indrodon Cope, Plesiadapis 

 Gerv., Protoadapis Lemoine. The remains are not complete, but the 

 dentition appears to have been sometimes slightly reduced (i -^ c i 

 p |^ m f ), and sometimes normal and in closed series, e.g. Lemuravus, 

 Pelycodus (i f c i p m f ), or in Adapis i \ c i p m -f. Some 

 of them had an entepicondylar foramen in the humerus, and a third tro- 

 chanter on the femur. In Anaptomorphus and Necrolemur the cranial 

 cavity is known to have been capacious ; these two genera have been 

 referred to the Tarsiidae. Many of these forms while agreeing 

 with lemurs in their skull (orbit, lacrymal foramen in front of 

 orbit, etc.) resemble the apes more closely in the form of their dentition, 

 and in the case of some of them there has been considerable difficulty 

 in deciding whether they should be referred to the Insectivora, the 

 Rodentia, or to the Lemuroidea. Chriacus, which was at one time held 

 to be a lemur, is now placed with the creodonts, while Mixodectes, 

 Plesiadapis, and Protoadapis have been referred to the Rodentia. As 

 might be expected from the imperfection of the remains, the whole 

 subject is in considerable confusion, and we can draw no satisfactory 

 conclusions as to the nature and affinities of these early forms. 



Order 2SL PRIMATES.* 



Plantigrade, usually pentadactyle animals with complete den- 

 tition, i f, bunodont premolars and molars, and two thoracic 

 mammae. The orbit is completely separated from the temporal 

 fossa, the pollex when present is always opposable (except in the 

 Hapalidae). The cerebral hemispheres completely or almost 

 completely cover the cerebellum, the uterus is without horns and 

 the placentation is metadiscoidal.'f 



* H. O. Forbes, Handbook to the Primates, 2 vols., 1894 (Allen's Natu- 

 ralist Library). Is. Geoffrey St. Hilaire, Catalogue methodique des Pri- 

 mates du Museum de Paris, 1851. Gray, Catalogue of Monkeys, etc., in 

 the Brit. Museum, 1870. Schlegel, Museum d'Histoire Nat. des Pays 

 Bas. L. 12, Simiae, 1876. Reichenbach, Die vollstandigste Naturges- 

 chichte der Affen, 1863. Wortman, Amer. Journal of Science, 16, 1903, 

 p. 345; 17, 1904, pp. 23, 133, 203. 



t The placentation is at first diffuse ; it becomes secondarily discoidal 



