240 MR. G. E. DOBSON ON CAPROMYS MELANURUS. [Apr. 1, 



inner border with the clavicular part of the pectoralis major), and 

 from nearly the whole outer border of the spine of the scapula ; the 

 fibres converging are inserted into the deltoid ridge of the humerus 

 along with those of the clavicular part of the pectoralis major. 



Latissimus dorsi (fig. 1, l.d), arising from several dorsal and 

 lumbar vertebrae, divides behind the brachial vessels and nerves into 

 two parts : one unites with the teres major muscle and, passing above 

 the brachial nerves, is inserted with it into the humerus ; the other, a 

 much smaller slip {l.d'), passes below the brachial nerves and is 

 inserted by a broad fascial aponeurosis into the humerus under cover 

 of the middle sternal part of the pectoralis major. 



The vessels and nerves of the arm, therefore, pass out between 

 the insertions of this muscle, as Meckel * noticed in Hyrax. 



Borso-epitrochlearis is well developed, arising from the external 

 surface of the latissimus dorsi, immediately before the tendon of the 

 latter is formed. 



Biceps has two heads — a long one from the upper margin of the 

 glenoid cavity, from which the main body of the muscle is derived, 

 and a much smaller which arises by a tendon (common to it and 

 the coraco-brachialis) from the coracoid process of the scapula. 

 These two heads, uniting about the middle of the humerus, form a 

 large muscular mass which is inserted by a strong tendon into the 

 ulna, and by a narrow tendinous slip (which passes across the 

 tendon of the brachialis anticus) into the adjacent margin of the 

 radius. 



Coraco-brachialis arises, as above described, with the short head 

 of the biceps from the coracoid process, and by a tendon common to 

 both, from which it separates at the lower margin of the tendon of 

 the subscapularis muscle, and, forming a small muscular mass, is 

 inserted into the lower third of the shaft of the humerus. 



Brachialis anticus arises, as usual, below the external tuberosity, 

 and, winding round the humerus, forms a broad tendon which, 

 passing between the two divisions of the tendon of the biceps, is 

 inserted into the ulna. 



Palmaris longus and flexor carpi ulnaris arise together from the 

 internal condyle and are inserted as usual. 



Flexor digitorum subli.mis, which arises as usual, forms the three 

 perforated tendons for the three middle toes ; that for the outer toe 

 is formed by the palmaris brevis. These tendons in passing into 

 the manus are covered by fascial arches, from which some of the 

 fibres of the large lumbricales arising from the tendons of the flexor 

 profundus also have their origin. 



Flexor digitorum profundus exhibits no peculiarity in its origin ; 

 it is formed by a superficial, an internal, and two deep heads, which 

 unite before crossing the carpus to form a very thick tendon, which 

 gives off in the palm a slender filiform tendon to the rudimentary 

 pollex, and four strong tendons to the four outer toes. 



Pronator radii teres, flexor carpi uhtaris, and flexor carpi 

 radialis present no peculiarities. 



1 ' TraitS General d'Anatomie Compare,' vi. p. 263. 



