ME. ST. GrEOEGrE MIYAET ON THE SKELETON ,0E THE PEIMATES. 
305 
the supraspinous fossa ; sometimes it is produced backwards over the infraspinous one 
It is much antroverted in Simia * and Nycticebus, and rather so in Ateles, Brachyurus, 
Callithrix, Chrysothrix, and the other Nycticebinse. On the other hand, in Lemur, 
Galago, and Tarsius, and also in Nyctipithecus, it is more or less produced over the 
infraspinous fossa. 
Generally the spine approaches very nearly to the border of the glenoid surface, but 
it remains rather distant from it in Man and the Chimpanzee, the Orang and Ateles, and 
still more so in the Gorilla and Hylobates. 
The spine also may or may not closely approach the ‘axillary margin towards the 
glenoidal end of the latter. It does so in the great majority of forms; but in Man, 
Perodicticus, Pithecia, Loris, and Nycticebus it recedes from it so as to produce a, 
greater width in the infraspinous than in the supraspinous fossa at that part. In the 
Orang and Mycetes it recedes also, and would produce a similar predominance of the 
infraspinous fossa but for the peculiar development of the supraspinous fossa which 
alters the proportion. The two fossae are about equal in breadth, near the border of 
the glenoid surface, in the Gorilla, Indris, and Arctocebus ; in all the others the supra- 
spinous one is in excess (except Tarsius and Cheiromys), especially in Cebus, Chryso- 
thrix, and the lower Simiidse. 
The base of the spine is generally grooved behind (below in Man) at its glenoidal end, 
most so in Cynocephalus and Mycetes. In Man, the Simiinae, Ateles, Indris, Loris, 
Tarsius, and Cheiromys, this groove, as far as I have seen, is absent. 
The acromion is long and narrow in Simia, Ateles, Mycetes, Pithecia, Chrysothrix, 
and Loris. It is short and ends very bluntly in the Semnopithecinse and Cynopithecinse, 
especially the latter (Plate XI. fig. 2). Sometimes the acromion expands, so as to send 
back a metacromion-like process, before reaching its distal end. This is the case in Man, 
Nyctipithecus, Hapale, and Troglodytes, and sometimes in Hylobates, and also in Lago- 
thrix, Lemur, and Galago. In the two last-mentioned genera, unlike the higher forms, 
this expansion projects backwards over the infraspinous fossa, instead of over the head 
of the humerus. The expanded part is very large, and it is concave externally. 
The coracoid process is large in Man and in all the Simiinse, Ateles, and the Le- 
muroidea. It is short in Mycetes and the lower Simiidse, especially in Cynocephalus 
(Plate XI. fig. 3). It advances much forward at its distal end in Man, the Simimae, 
Ateles, and some- of the lower Cebidse (e. g. Callithrix), and in the Lemuroidea. In the 
others its distal end scarcely, if at all, advances in front of the glenoid surface. 
The ridge or process for the attachment of the coraco-clavfcular ligament is very 
little marked in Man, the Orang and Gorilla, Lemur, Loris, and Cheiromys. It is very 
small, though distinct, in Indris, moderate in the Chimpanzee and Hylobates, and larger 
in the other forms, though in Mycetes it is small, apart from the peculiar fiat process of 
that genus, with which process it comes ultimately to unite. 
* Mentioned by Professor 0 >ven, Trans. Zool. Soc. yob. i. p. 864, and by Vrolik, Cyclop. Anat. & Phys. 
yoI. iv. p. 203. 
