698 MJiissns. u. o. a. wijS'dle xyu ii\ g. parson's ok [Dec. i7, 



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

 the muscle is absent. 



Sapinator lonc/us. — This muscle was found in the Hippopotamus 

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

 (63, 64), and in the Elephaut (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 Ouvier 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 \ 



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

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

 thinking this is that we know that the extensor carpi radialis 

 loDgior is so supplied. 



Extensor carpi radiales longior ^' hrevior. — It is only occasionally 

 that these two muscles are found distinct in the Ungulates, 

 more frequently they are either fnsed or the extensor lougus 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 off which joins the extensor communis tendon to 

 the index. In the Suidse (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), Tragulidae (20, 21), with the exception 

 of Dorcatherium, Cervidse (25, '2Q, 27, 28), GiraffidsB (29), Bovidae 

 (33, 35, 36, 37, 38, 40, 43, 49), Equida3 (bQ, 58), and Ehino- 

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

 composed of the brevier; 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 patellae in the knee 

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

 the Water- Chevrotain (DorcatJierium 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 Tapiridse there may be a single insertion 

 into the thii-d luetacarpal (54), or a small slip may be given off for 

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

 longior and brevier are distinct and separate muscles. In the 

 Elephantidic (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 



^ l*08riib]y this is supinator brevis. 



