1901.] THE MUSCLES 01" TlID trXOUIiATA. 0^7 



ini'raspiuatus. Lesbres (^V.) says that in the Horse aud Pig a slip 

 comes from the dorsal angle of the scapula. We have never found 

 a separate slip of the deltoid from the angle, but the origin 

 from the infraspinatus fascia is so extensive that it reaches the 

 dorsal (posterior) angle, and in Lesbres's specimens was probably 

 thickened there. The nerve-supply is in all cases the circumflex. 



Subscapuhcris. ^This is a comparatively small muscle seldom 

 covering more than two-thirds of the ventral surface of the 

 scapula, it usually rises by a series of fleshy digitations with 

 fibrous septa between them; in the Hyrax (68) there are four or 

 five of these, in the Hippopotamus (1) three. The insertion as 

 usual is into the lesser tuberosity. 



Bronn (VI.) describes a muscle in the Horse and Pig which he 

 calls " suhscapularis accessorius," and he says that it is inserted 

 into the posterior aspect of the head of the humerus and capsule 

 and is supplied by the circumflex nerve (u. axillaris). The uerye- 

 supply and insertion show that this is not the axillary bundle of 

 the.subscapularis, which in some animals is very distinct.. 



Paterson and Dun noticed a muscle in the Indian Elepliant 

 (79) which rose from the axillary part of the subscapular fossa 

 anterior to the triceps and passed below the capsule of the 

 shoulder to be inserted into the posterior surface of the humerus 

 just beloiv the head; it was supplied by the circumflex nerve, and 

 it is evidently the same as the muscle quoted above from Bronn, 



.These authors call it the subglenoid muscle, and we think that 

 this name had better be retained, since it corresponds with nothing 

 we have hitherto met with in mammalian myology. It is appar- 

 ently a muscle which occurs occasionally in Ungulates and is not 

 confined to any one .family. 



The suhscapularis is usually supplied by two nerves from the 

 upper part of the brachial plexus. 



Siipraspinatus.- — This is a larger muscle than the infraspinatus, 

 and rises not only from the supraspinous fossa but from a fibrous 

 septum between it and, the cephalic edge of the subscapulnris. At 

 its insertion it usually divides to embrace the long tendon of the 

 biceps. In the .Brocket Deer (27), Antelope (49), and Horse (56) 

 the insertion was entirely fleshy, but in the Pigs (11, 14) it was 

 tendinous. In the Horse, Ox, Sheep, Antelope, and Pig it is 

 supplied by the suprascapular nerve. 



Infraspmatus.--Vn\s_\ii smaller than the last and is chiefly 

 remarkable . for , having a small bundle of fibres near the axillary 

 border separated .from the rest. This bundle is said by Chauveau 

 and Lesbres to be peculiar to the Solipeds, but Murie (XVII.) 

 describes what is evidently the same thing in the Tapir (55) as an 

 extra .teres minor, aud liaughton (XV.) says it is present in the 

 Goat.. .. . ... 



In .the Horse .this .muscle has received many names, the chief 

 being scapulo-humeralis posticus, flexor brachii minimus, abductor 

 trochiteri_en, and infraspinatus secundus. We, should prefer to 

 use the last of these, but we are not sure of the nerve-supply; 



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