700 MESSRS. B.C. A.. W1NDLR AST) P.O. PABSON8 OB ; Dec. 17. 



another in pulling the forearm and arm forwards over the loot, as 

 the varying position of the phalanges gives each one a temporary 

 advantage. 



Extensor minimi digiU [Extensor digitomm lateralis). — This 



muscle rises from the external condyle and deep fascia and occa- 

 sionally gains some fibres from the upper end of the radius; Its 



usual insertion is either into the annularis or minimus or both 

 digits. We have often noticed that the tendon to the annularis 

 i< inserted into the middle phalanx, leaving the extensor com- 

 munis to supply the terminal phalanx, but whether this is the 

 normal arrangement or not our material does not allow us to say. 



In the Hippopotamus tendons may pa^s to the -Ith and 5th 

 dibits (1) or to the 5th only (3). In the Snidae it is usually the 

 4th and 5th (annularis and minimus) (5, 0, 7, 13, 14), but some- 

 times the minimum only (4. 11). In the Camel (15, 17) annularis 

 only. In the Chevrotain (20) and Water-Chevrotain (23) annu- 

 laris and minimus. In the Ceroids usually to the annularis onlv 

 (Bell XIV. 27, 28). but Lesbres found it going to annularis and 

 minimus. In the Giraffe (29) and all the Bovida; (32, 33, 34, 35, 

 36, 37, 38, 30. -10, 40, 41, 49) to the annularis only. In this last 

 family Chauveau describes an extra origin from the upper end of 

 the radius. In the Tapir (52. 54, 55) there are slips to the annu- 

 laris and minimus. Murie found in his animal (55; three muscles 

 coming from the external condyle in addition to tin- extensor 

 communis, two of these went to the annularis ami minimus and 

 one to the minimus only; he homologizes the.se muscles with the 

 peroneals. 



In the Equidse (56, 58, '30; the muscle i- verj small and has 

 lost its condylar attachment and slipped down to the external 

 lateral ligament and upper part of radius and ulna. lis inser- 

 tion is into the proximal phalanx of the medius. In the Rhino- 

 ceros (63, 64) the insertion is into the medius and annularis. 

 In the Hyrax (67, 68) there were tendons for the annularis and 

 minimus, the annularis going to the proximal phalanx in (67), and 

 to the head of the metacarpal according to Mivart and Murie 

 (XXIV.) in (68). In Meckel's specimen (71) there was only one 

 tendon, which went to the proximal phalanx of the minimus. 



In the Elephant the muscle rises from the condyle and ulna 

 (71. 78), it is inserted into the annularis and minimus (7 1. 77 I or 

 into the minimus alone (78). The nerve-supply is from the 

 posterior interosseous. 



■ Extensor carpi uhuvris] also called posterior ulnaris, idnaris 

 externus, and Jitxor metacarpi extemvts. — This muscle iu the 

 Ungulates is in most instances a powerful flexor of the carpus, 

 and passes from the external condyle to the piriform bone, just 

 before which it often joins the tendon of the flexor carpi ulnari< ; 

 it also usually gives off a slip to be inserted into the fourth or 

 fifth metacarpal, if it is present; The muscle is well developed 

 in the Hippopotamus (1,'S), but in the Suidae (4, 5, 7, 11, 13. 14) 

 it is small and in some cases almost entirely tendinous. In the 



