rjREGORY: NOTHANCrUS, AN AMERICAN EOCENE PRIMATE 



107 



trochlea. The calcaiKHiin is widened and flattened on the i)lantar suil'ace below and has an expanded 

 tuber. Metatarsals II-V are all elongate and of subequal length. The distal phalanx of the hallux is 

 narrow instead of broadly spatulate; the distal phalanges of digits II-V are very slender and slightly 

 extended distally; they evidently carried very narrow nails which in Cebus are often almost claw-like. 



Hapale differs from N^oiharctus in the markedly less divergent hallux, which is held nearly parallel 

 to the other digits; in correlation with this the peroneal process of the end of metatarsal I is much reduced 

 and all the digits end in claw-like nails, the first showing some traces of the flattening. For reasons 

 given elsewhere it seems probable that these "claws" of Hapale are secondarily compressed nails and 

 that Hapale is merely a specialized cebid with squirrel-like habits. 



The pes of the Old World monkey Macacus differs from that of Notharctus as follows: the trochlea 

 of the astragalus is widened, with a sharp internal rim; the neck di\'ei'ges less from the trochlea and the 

 head is more expanded; the calcaneum is shorter and wider; the navicular is much widei' and has nearly 

 parallel upper and lower facets; the distal facet of the entocuneiform is broadly convex rather than con- 

 cave or saddle-shaped; the peroneal process of digit I is wide but less elongate; the cuboid is shorter 

 and broader and so also are the meso- and ectocuneiform. The proximal phalanges are more sharply 

 curved and flattened beneath; the distal phalanges are pointed, but show no superior dorsal groove. 

 All these characters of Macacus are probably correlated with its more or less terrestrial and sul)cui'S()i'ia,l 

 habits. 



Comparative Measurements of Pes 



Met.atarsal I, Length 



I, Width of Distal End 

 II, Length 



II, Width of Dislal End 

 III, Lengtli 



III, Width of Distal End 

 " IV, Length 



IV, Width of Distal En.l 

 " V, Length 



V, Width of Dislal End 

 Hallux, Length 



Astragalus, Length, trochlea lo head 

 Calcaneum, Length 

 Navicular, Mid-lenglh 



" Breadth 

 Cuboid, Length 

 " Breadth 



NotharduH 



osbnrni 

 No. 11474 



6.4 

 23. 



4. 

 2,3..^ 



4.3 



20. 

 4.3 

 44. 

 14 o 



9.2 



8.4 



Noihardus 

 t!/nnn,Ns 

 Xd. 1147.S 



motigoz 

 No. 12822 



4.3 

 26.5 



4. 

 26.5 



4. 

 25 



3.9 

 4,S , 5 

 16. 

 23. 



7 . 



9.6 



9. 



7.3 



mongoz 

 No. 31254 



25. 



4.3 

 24.3 



3.7 

 24. 



4.7 

 23. 



3.7 



9 . 5 

 9, 



Lemur 

 pari lis 

 No. 18040 



3S. 



6.4 

 36. 



5.3 

 35 . 



5.4 

 .33. 



5.3 

 32 . 



51 . 



IS. 5 

 29. 

 S. 

 1 2 . 

 12. 

 11 . 



THE VERTEH1{.VL COHMX OE yOTIIAHCTl'S 

 The principal specimens in which the backbone is represented are Amer. Mus. No. 11474, the type 

 of Notharctus osborni; No. 11478, referred to Notharctus tyrannus; and No. 11473, referred to N. osborni. 

 A few vertebrae are associated with other specimens of Notharctus. In no individual is the column com- 

 pletely preserved, but by a careful comparison of these specimens with each other and \\\\h those of 

 existing lemurs and other primates the chief features of the l^ackbone are revealed. 



