440 EK. C. MacDowell. 
ing the main belly of the triceps, just proximal to the insertion of 
the lattissimo condyloideus. The whole muscle is characterized 
by the close interlacing of the parts. “The Macacus shows a sep- 
aration of three parts half way down the arm. 
Hepburn found this muscle strongly developed in all anthro- 
poids, and Beddard describes it asin man. Bardeen says a fourth 
head is frequently found in man as a variation. Le Double re- 
ported 20 such cases. 
C. Mutscies or THE FOREARM 
The Palmaris longus arises in the chimpanzee from the common 
tendon from the internal condyle external to the flexor carpi 
radialis, and is closely joined to it. It becomes separate 8 cm. 
from its origin and is inserted into a slender tendon which is in- 
serted into the proximal, radial aspect of the carpal ligament 
and the neighboring palmar fascia. 
Beddard, Vrolik, Champneys, and Rolleston (quoted by Champ- 
neys) found the same arrangement in the chimpanzee. In the 
orang, Duvernoy and Michaélis describe it as being very strong. 
Primrose found a slip to the thumb from which arose a part of the 
abductor brevis. It is wanting in the gorilla (Hartmann, Hepburn, 
and Duvernoy). Forster found it well developed in his ‘‘ Papua 
neugeborenen.”’ Bardeen saysthat it was oncea third flexor to the 
digits (flexor longus superficialis). MceMurrich states that this 
muscle seems to have been the first to separate from the common 
flexor mass. Adachi reports it. lacking in 20.4 per cent of Euro- 
pean men but only in 3.9 per cent of Japanese. Le Double did 
not find it in 11.2 per cent of bodies. 
The Flexor digitorum sublimis (perforatus) is characterized in 
the chimpanzee by the extreme separation of the bellies going to 
the different digits. Although closely bound together by fascia, 
the bellies can be traced to definite and distinct origins. 
A. The division for the index finger arises from the coronoid 
process of the ulna and from the tendinous sheath of the flexor 
carpi radialis by two groups of loosely bound fibers, which become 
at once incorporated into the main belly. The fibers are inserted 
