1901.] THE A1USCLES OF 'J?HK UNGULATA. 701 



Tragulida? (20, 21, 23), Cervida (25, 26. 27. 28), and Bovidaa (32, 

 33, 34, 35, 36, 38, 39, 40, 41, 43, 48, 49) it is very well marked 

 and forms the chief flexor ot' the carpus. In the Tapir (54) it is 

 chiefly inserted into the metacarpal hone of the minimus. In the 

 Equidae (56, 58, 59, 61) one part goes as usual to the pisiform 

 with the flexor carpi ulnaris, the other is inserted into the rudi- 

 mentary fourth metacarpal. In the Rhinoceros (ij-'y) it is figured 

 but not described, it seems to he largely inserted into the meta- 

 carpal bone of the annularis. In the Hyrax (67) and Elephant 

 (74,77,78,79) the muscle, though still an important tiexor, is 

 chiefly inserted into the metacarpal of the minimus. The con- 

 version of this muscle from an extensor to a flexor is correlated 

 with two compensatory changes : firstly, the extensor carpi radialis 

 is much enlarged and does all the extension of the carpus; secondly, 

 the tiexor carpi ulnaris is reduced in importance and its olecranal 

 head is often absent. 



The nerve-supply is the posterior interosseous in the Pig, Duiker- 

 bok, Sheep, Hyrax, and Elephant. 



Supinator brevis. — This muscle is described by Bronn as 

 entirely absent in the Ungulata, and with two exceptions we can 

 confirm his statement. In the Pig (A".) Lesbres found it once, 

 and Chauveau (II.) says that in this animal it is extremely thin. 

 In our specimens of Suidae (11, 14") no trace ot it could be found. 

 In the Hyrax (68) we found it as a mere tendon, which is con- 

 tinued into the superficial plane of the extensor ossis metacarpi 

 pollicis ; but in Mivart and Murie's animal (67) there is no men- 

 tion of it, though possibly the muscle which these authors describe 

 as supinator longus may, in reality, be supinator brevis. The 

 muscle was so aborted that we could trace no nerve to it. 



Extensor ossis metacarpi pollicis. — In the Hippopotamus ('■>) 

 this rises from the shaft of the ulna, and is inserted (1) into the 

 radial side of the carpus. 



Tn the Suidae (4, 5, 7. 'K II. 13, 14) it is small, and rises from 

 below the middle of both forearm bones to lie inserted into the 

 proximal end of the metacarpal bone of the index. 



In the Tragulida- (20, 21. 22. 23) it rises from the ulna, and 

 has the same insertion as in the Suidae ; in our specimen (21 | it 

 was almost entirely tendinous, bul in Kinberg's (20) seems to be 

 well developed, since il rises from the lower half of the ulna. In 

 the Camelidae (15, 16), Cervidac (26, 27, 28), Giraffidae (29), and 

 Bovidaa (32, 33,36, 38, 39, 13, 18, 19) u is inserted into the 

 canon-bone (3rd and it h fused metacarpals), bul sometimes (26 

 27, 28, 1 ( . ( ) a sesamoid hone is found, in its tendon which, from 

 careful examination of the Duiker-bok (49), we believe is the 

 vestige of the index metacarpal. In the Tapir (54, 55) it is 

 well developed, rises from almost the whole length ol the radius 

 and ulna, and is insetted into I he index metacarpal. In the 



Horse, Bronn (VI.) Bays it is absent, hut Chauveau (II.) and 

 Lesbres (V.) agree that it is present, though feeble, and inserted 

 into the rudimentary index metacarpal. Iii the Rhinoceros (63, 

 I i;..< . Zool. Soc. L901 . Vol. 1 1 No. X I, VI. 16 



