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ME. ST. GEOEGE MIYAET ON THE SKELETON OE THE PEIMATES. 
more rounded still in the other forms, except the Cynopithecinse, where sometimes it 
is better defined than in Man, as sometimes also in Cebus, Lemur, and Galago. 
The degree of distinctness of the ridges and depressions for muscular attachment is 
subject to much individual variation. 
In the Cynopithecinae, Ateles, and sometimes in Lemur and Nycticebus, there is a 
marked depression for the supinator brevis, I have not observed it elsewhere. 
The ridge giving origin to the flexor sublimis digitorum is marked in Man and the 
lower Simiidse (especially Cynocephalus). I have also found it marked in Chrysothrix, 
Indris, and Arctocebus ; less, or not at all so in other forms. 
The excavation in which the flexor longus pollicis takes origin is marked in Man, 
sometimes in Hylobates, in the Simiidse other than the Simiinse, in Cebus, Pithecia, 
Lemur, Nycticebus, and Arctocebus. In others I have found the surface flat or rounded. 
A similar depression for the extensor pollicis is sometimes very marked in the lower 
Simiidse ; it is also marked in Man (sometimes) and in Chrysothrix, and slightly so in 
Indris. In the other genera I have only observed a flattening of the bone at the most. 
The insertion of the pronator teres is sometimes marked by a roughness of the surface. 
This I have seen in Man, the Orang, Cynocephalus, Mycetes, Chrysothrix, Hapale, and 
Nycticebus. A decided fossa is occasionally present at that spot as, sometimes at least, 
in Macacus, Callithrix, Brachyurus, Lemur, Galago, Perodicticus, Arctocebus, Tarsius, 
and Cheiromys. 
The inferior margin of the anterior, or flexor, surface is now and then much produced, 
as in Man and Cynocephalus ; sometimes only the ulnar side of the inferior margin is 
prominent, as in Ateles, Mycetes, Lemur. 
In the Nycticebinse there is a process, at the lower end of the radius, projecting ulnad 
and articulating with the head of the ulna. A rudiment of this process exists in Indris. 
The lower end of the posterior surface is generally traversed by a median longitudinal 
ridge, which appears to attain its maximum in Cynocephalus. 
The styloid process is constant. It is large in Man and the Simiinse. shorter in the 
Cynopithecinae, Cebidee, and Hapale, very short in Indris, Lemur, and Galago, but 
longer again in Nycticebus and Arctocebus. 
A prominence for the insertion of the supinator longus is more or less marked in 
Troglodytes*, Simia, and Hylobates. It is much so in some of the Cynopithecinae, and 
in Cebus, Lemur, and Galago. 
The foramen for the medullary artery is situated above the middle of the bone, and 
is always directed upwards, except in Ateles f and Arctocebus. In Ateles the long 
groove which the artery makes on the surface of the bone is remarkable. 
The groove for the tendon of the extensor ossis metacarpi pollicis is almost always 
very marked. In Hylobates it equals in size that for the tendons of the radial extensors, 
* Owex, Trans. Zool. Soc. vol. v. p. 7. 
f Not always downwards in Ateles, however ; for in a skeleton of A. Geolfroyii in the British Museum it is 
directed upwards in one arm and downwards in the other. 
