424 
ME. ST. GEORGE MIYART ON THE SKELETON OF THE PRIMATES. 
ARCTOCEBUS. 
Proportion of supra- to the infraspinous fossa very large ; free edge of spine of scapula 
much flattened ; anterior margin of scapula with a convexity as in Loris ; great tuberosity 
of humerus not rising to the level of the summit of its head ; internal condyle promi- 
nent, but no supracondyloid foramen ; index with only two phalanges ; pollex reaching 
altogether beyond index and to ultimate phalanx of third digit, which third digit is 
remarkably short; peroneal trochanter very small, and not projecting peronead beyond 
the shaft of the femur ; trochanteric fossa very small ; tibial trochanter a large plate-like 
process, exceeding the peroneal trochanter in size ; no third trochanter ; hallux reaching 
to the end of the index digit of the pes. 
TARSIHLE & CHEIROMYIDiE. 
For the main peculiarities of these families see above, where they are the last two of 
the “ Exceptional forms ” given above. 
To sum up the results of the foregoing observations, the Primates appear to present 
us (as regards their appendicular skeleton) with six principal types of structure, 
namely, (1) Homo, (2) Simia, (3) Cercopithecus, (4) Nycticebus, (5) Lemur, and 
(6) Tarsius. The first, however, has relations both with the third and fourth, some 
of the Nycticebinae resembling Man more than all, or almost all, the other Primates 
in the proportion borne by the arm, without the manus, to the spine ; in the propor- 
tion borne by the radius and ulna to the same ; in the length of the pollex as compared 
with that of the longest digit ; in the proportion borne by the tibia to the humerus 
and to the femur ; in the length of the pes as compared with that of the tibia ; in the 
marked anterior vertebral angle of the scapula ; in the small supraspinous fossa ; in 
the excess of the infraspinous fossa over the supraspinous one near the glenoid surface ; 
in the short symphysis pubis ; in the very peculiar tuberosity of the ischium. More- 
over, one or more of the Nycticebinae differ from the other Lemuroidea and approxi- 
mate to Man in the greater or less degree of sigmoid curvature of the clavicle, and in 
the absence, in one genus, of the supracondyloid foramen in the humerus. 
Besides the above six types, other forms show, as we have seen, more or less 
marked peculiarities ; and perhaps the affinities between the various groups of the order 
(as regards the characters offered by their appendicular skeleton exclusively) may be 
fairly represented under the symbol of a tree. The trunk of such a tree divides into 
two main branches, for the Anthropoidea and Lemuroidea respectively. 
The first main branch gives off a secondary one, which represents Man *, and then 
* It should be home in mind that this is only an attempt to express the degrees of resemblance existing 
amongst the appendicular skeletons of Primates, not the affinities indicated by their osteology generally, still 
less that evidenced by the totality of their organization. It is, in great part, the ossa innominata -which cause 
Man to diverge so from the other Anthropoidea. 
