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 Indrodon, 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 Indrodon 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 premolars are each three. To the same family, which has been termed Anaptomorphidae, is referred the genus Anaptomorphus, which has been specially compared to Tarsius. This small animal has a Lemurine face with huge orbits. It has a premolar less than Indrodon. It has been ascertained that A. homunculus had an external lachrymal foramen.[1]
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 affinities. 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 Tomitherium, an "undoubted Primate," shows the same feature. If Chriacus is a Lemur it is an earlier type than those
- ↑ See Schlosser, Beiträge Pal. Osterr. Hung. 1888; also Osborn and Earle, Bull. Amer. Mus. Nat. Hist. vii. 1895, p. 16.
