522 
Proceedings of the Royal Irish Academy. 
Bracliialis anticus ("08) arises from the anterior and inner (outer, 
Professor Humphry) aspect of the humerus, and is inserted into the 
ulna beside the gieno-ulnar part of the biceps. In Professor Macalis- 
ter's specimen the tendon of insertion was double, one radial, slightly 
connected with the insertion of biceps humeralis, and one ulnar, behind 
scapular biceps. 
Triceps is normal in all; t. longus (•12) with a small origin; t. 
humeralis ("18) had its two heads imperfectly separated by the 
musculo- spiral nerve in Arctopithecus. 
Dorso-epitrochlearis ("02) takes origin from the triceps, and has 
the usual insertion. 
Anconeus externus ('01) is distinct, normal in all, insertion, upper 
fifth of ulna in Arctopithecus. 
Anconeus internus ('01) (epitrochleo-anconeus) arises from the 
inner condyle of the humerus, and crosses the ulnar nerve in all, over- 
lying (underlying. Professor Macalister) the flexor carpi ulnaris, and 
is inserted into the olecranon process. 
Pronator teres ('10) arises from the inner condyle of the humerus, 
and has a double insertion into the lower half of the radius, and the 
anterior surface of the wrist joint. The latter insertion is not men- 
tioned by Professor Humphry. 
Pronator quadratus ('02) extends over the lower one-sixth of the 
fore-arm (lower one-eighth, Meckel), and is described by Professor 
Humphry as having a broader attachment to the ulna than to the 
radius. 
Flexor carpi radialis profundus, a small muscle in Arctopithecus, 
arises from the ulna and runs down at an angle of 40° with the fibres 
of pronator quadratus, to the deep fascia of the wrist. It was not - 
found either by Professor Macalister or Professor Humphry. 
Plexor carpi radialis ('02) takes origin from the inner condyle of 
the humerus, and is inserted into the base of the first metacarpal and 
trapezium. The latter insertion is not described by Professor Hum- 
phry. 
Palmaris longus ("04) arises from the same place as the last, and 
is inserted into the palmar fascia, pisiform and unciform. Professor 
Humphry found the insertion into the process of the scaphoid that 
descends towards met. L" 
Plexor carpi ulnaris ("09) is bicipital, one head from the inner con- 
dyle, and one from the whole length of the ulna. The two parts are 
separated by the ulnar nerve, underlie the anconeus internus, and are 
inserted into the unciform, annular ligament, and base of third meta- 
carpal. Professor Macalister found the second head from the olecranum 
alone, and the two parts lay over the anconeus internus, whilst the 
insertion included the pisiform as well as the parts mentioned above. 
Professor Humphry describes it as being inserted into the distal part 
of the pisiform, and the fourth and fifth metacarpals. 
Plexor digitorum ('95), an enormous muscle partly divisible into 
condyloid, radial^ and ulnar portions, corresponding to the origins 
