698 MESSES. B. 0. A. WINDLB A.MD I . <-. PARSONS OX [Due. J 7. 



In our Tapir (54) and in all the other Ungulates we examined 

 the muscle is absent. 



Supinator longta, — Tliis muscle was found in the Hippopotamus 

 (1) but not in (3), in the Tapir (52, 53, 54, 55), in the Rhinoceros 

 (63, 64), and in the Elephant (73, 74, 78, 79); in the latter 

 animal it is prolonged beyond the styloid process of the radius to 

 one of the carpal bones, apparently the lunare ; in Cuvier and 

 Laurillard's specimen (77), however, it is absent. In our Hyrax 

 (68) it was entirely wanting, but in Mivart and Murie's (67) it is 

 described as very diminutive and inserted into the radius near 

 its neck l . 



In other Ungulates the muscle is absent. When it is present 

 it is doubtless supplied by the musculo-spiral; our reason for 

 thinking this is that we know that the extensor carpi radialis 

 longior is so supplied. 



Extensor carpi radiates longior §■ brevior. — It is only occasionally 

 that these two muscles are found distinct in the Ungulates, 

 more frequently they are either fused or the extensor longus is 

 suppressed. In the Hippopotamus there is only one muscle which 

 is inserted into the metacarpal bone of the medius (1, 3), but in (3) 

 a slip is given oft' which joins the extensor communis tendon to 

 the index. In the Suida? (4, 5, 7, 10, 11, 13, 14) the brevis only is 

 present and is inserted into the metacarpal bone of the medius. 

 In the Camelidae (17, 18), Tragulidse (20, 21), with the exception 

 of Dorcatherium, Cervidae (25, 26, 27, 28), Giraffidas (29), Bo\ idae 

 (33, 35, 36, 37, 38, 40, 43, 49), Equidae (56, 58), and Rhiuo- 

 cerotidse (63, 64) there is only one muscle, which at least is chiefly 

 composed of the brevior; it is very large and forms a broad strap- 

 like tendon, which plays over the lower end of the extensor 

 surface of the ulna and is inserted into the dorsal surface of the 

 base of the large canon-bone, which is composed of the third or 

 third and fourth metacarpals ; it is the important extensor of the 

 carpus, and reminds one of the ligamentum patella) in the knee 

 except that no sesamoid bone (patella) is developed in it. En 

 the Water- Che vrotain (DorcatTierium 23), which, possibly as an 

 adaptation to its swimming-habits, retains a more generalized 

 arrangement of its forearm musculature, the extensor longior is 

 also present. In the Tapiridae there may be a single insertion 

 into the third metacarpal (54), or a small slip may be given off for 

 the second as well (55). In the Procaviidae (67, 68, 71) the 

 longior and brevior are distinct and separate muscles. In the 

 Elephantidae (73, 74, 77, 78, 79) there is one muscle but it ends 

 in two tendons for the second and third metacarpals. 



With regard to the nerve-supply, the musculo-spiral supplies it 

 in the Pig (11), Peccary (14), Brocket (27), and Elephant (79), 

 the posterior interosseous in the Duiker-bok (49). 



Extensor communis digitorum. — This has the usual origin from 

 the external condyle and is usually inserted into the middle and 



1 Possibly this is supinator brevis. 



