514 ORIGINAL ARTICLES. 



the lower third of the humerus. Taking its origin by fleshy fibres 

 alongside of the long head of the Biceps and the Coraco-brachialis, and 

 receiving fibres from them, was a muscular slip, described as tres mince 

 in the Chimpanzee (Yrolik, 1. c. p. 19), which, after accompanying 

 the long head of the Biceps for 2 J inches, leaves it to be inserted into 

 the humerus and intermuscular septum, immediately below the in- 

 sertion of the Corecobrachialis, and alongside of the internal portion 

 of the Triceps. This slip is not mentioned by Duvernoy as occurring 

 in the Orang, but he found it in the Chimpanzee and Gorilla : in the 

 latter, it joined the Borso-epitrochlien. It did not occur in the Cebus 

 or Magot, and Cuvier* has not figured it in any of his plates. 



This slip is a frequent occurrence in the human subject, the 

 Biceps being subject to many variations. 



The Triceps differed from that of man only in having the long 

 head of greater proportionate strength : it had a large insertion, cover- 

 ing a space of one inch and seven-eighths into the inner and lower 

 edge of the scapula. 



In examining the muscles which move the hand of the Orang, we 

 find that, whilst the extensor muscles closely correspond with those 

 of man, the flexor muscles are modified, in order to strengthen the 

 hand for grasping, while the capability for varied and delicate move- 

 ments must be impaired. 



The Supinator Longus was large, its origin covering a space of 3|- 

 inches on the humerus, and some of its fibres appearing to interlace 

 with those of the long head of the Triceps as it passed downwards. 



The Extensor Carpi Badialis Longior arose from the external 

 condyloid ridge of the humerus. The lower two-thirds of this muscle 

 were tendinous : it was inserted into the radial side of the metacarpal 

 bone of the index. 



The Extensor Carpi Badialis Brevior was larger and stouter than 

 the preceding muscle, and had a similar insertion into the meta- 

 carpal bone of the middle finger. 



The Extensor Communis Digitorum presented almost exactly the 

 same appearance as in man. In the Chimpanzee, according to Du- 

 vernoy, the portion for the index finger is distinct, from its origin. 



The Extensor Minimi Digiti arose alongside of the Extensor 

 Carpi Ulnaris from the ulna and intermuscular septum, passed through 

 a distinct sheath of the annular ligament, and split into two tendons 

 inserted into the ring and little fingers. In the Chimpanzee, it is 

 inserted into the little finger only. The Gorilla has the tendon 

 strongly connected with that of the Extensor Communis; the muscular 

 portion seemed also to form part of the Extensor Communis. (Du- 

 vernoy, 1. c. p. 97.) In the Cebus, it formed part of the same mus- 

 cular belly as the Extensor Communis, but soon separated from it, 

 and was inserted as in the Orang. In the Magot, its origin, dispo- 

 sition, and insertion all resembled those in the Orang. 



The Extensor Indicis, instead of being inserted only into the 

 index, was flattened out, and inserted chiefly into the base of the 



* Anat. Comp. Eecueil de Planches dc Myologic, detainees par G. Cuvicr. 



