552 ORIGIN OF LEMURS CHAP. 
One of these early forms is referred to the genus Mixodectes, a 
genus which has been placed, though with a query, in the order 
Rodentia. It appears, however, to be a Lemuroid, and is of 
American range. The incisor teeth have been held to argue 
that it lies on the direct track of Chiromys.; but other features, 
more especially the form of the astragalus, have been used to 
argue the justice of the inclusion of this type within the order 
Rodentia. Allied, as it is supposed, to this form is Jndrodon, 
also of the lowest Eocene deposits of the United States. Indrodon 
malaris is known from fragments of nearly all parts of the 
skeleton. They indicate the existence of a creature of about one- 
half the size of Lemur varius. It had slender limbs and a 
long and powerful tail. The humerus, as in so many archaic 
beasts, has an entepicondylar foramen. The femur has three 
trochanters, and the fibula articulates with the astragalus. It is 
not always easy to distinguish these primitive mammals from 
each other, so that the minutest of characters have to be called 
in to our assistance. One of the contemporaneous groups with 
which these early Lemurs might be confused is that of the 
Condylarthra ; it is important, therefore, to note that in Jndrodon 
the calcaneo-cuboidal articulation is nearly flat, and not bent as 
it is in the former group. The teeth are of the tritubercular 
pattern. The incisors are not known, but the molars and pre- 
molars are each three. To the same family, which has been 
termed Anaptomorphidae, is referred the genus Anaptomorphus, 
which has been specially compared to TYarsius. This small 
animal has a Lemurine face with huge orbits. It has a pre- 
molar less than Jndrodon. It has been ascertained that A. 
homunculus had an external lachrymal foramen.’ 
Another family, that of the Chriacidae, appear to hover on 
the border line of Lemurs and Creodonts, having been referred to 
both by various palaeontologists. Professor Scott suggests their 
Lemurine or at least Primate relationships, while Cope urged 
their Creodont aftinities. A difficulty raised by Scott was, that 
in Chriacus the premolars of the lower jaw were spaced. But it 
appears that this is not fatal to their inclusion in the Primates, 
since Zomitherium, an “undoubted Primate,” shows the same 
feature. If Chriacus is a Lemur it is an earlier type than those 
' See Schlosser, Beitrdge Pal. Osterr. Hung. 1888 ; also Osborn and Earle, Bul. 
Amer. Mus. Nat. Hist. vii. 1895, p. 16. 
