74 



(JREGORY 



XOTIIAUCTCS, AN AMERICAN EOCENE PRIMATE 



In Microcebus, of the same family, which has veiy delicate limbs, the supinator crest flares backward 

 ■somewhat as in Tarsius, but otherwise the humerus is like that of other lemurs. 



The humerus of Propithecus is more specialized than that of Nothardus in the following characters: 

 (1) The shaft is elongate. 



Fig. N. Comparatix t" series: right luimeri of yoflutrdii.s and LcpUciimr. Xatiiral size. 



A^. Nolharctus osborni. Amer. Mus. No. 11474. Front view. 

 B^. Lejrilemur mustelin us. Amer. Mus. No. 31251. Front view. 

 A-, IP. Back view of same specimens. 



A-\ IP. Inner side view. 

 A'*, IP. Outer side view. 



(2) The deltoid crest is small and limited to the upper third of the shaft ; it has a curled-over pectoral 



edge, protruding along the middle portion of the crest, above the fossa for the tendon of the 

 latissimus. 



(3) The shaft is flattened in its mid-section. 



(4) The supinator crest is less flaring and narrower transversely. 



(.")) The inner lip of the trochlea is abortive, as the forearm is habitually supinated. 



