700 MESSRS. B. C. A. WINBLE ANB T. G. PARSONS ON [Dec. 17, 



anotheriu piilling Mre forearm and arm forwards over the foot, as- 

 the varying position t)f the phalanges gives each one a temporary 

 advantage. 



Extensor mimmi diglti (^Extensor digitorum 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 

 is inserted into the middle phalanx, leaving the extensor com^ 

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

 normal an-angemeut or not our material does not allow us to say;- 



In the Hippopotamus tendons may pass to the 4th and 5th 

 digits (1) or to the 5th only (3). In the Suida3 it is usually the 

 4th and 5th (annularis and minimus) (5, 6, 7, 13, 14), but some- 

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

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

 laris and minimus. In the Cervidte usually to the annularis only 

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

 minimus. In the Griraffe (29) and all the Bovidse (32, 33, 34, 35, 

 3(3, 37, 38, 39, 40, 40, 41, 49) to the annularis only. In this last 

 family Chauveau describes an extra origin from the uj)per 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 the extensor 

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

 one to the minimus only; he homologizes these muscles with the 

 peroneals. 



In the Equida3 (56, 58, 60) the muscle is very small and has 

 lost its condylar attachment and slipped down to the external 

 lateral ligament and upper part of radius and ulna. " Its inser- 

 tion is into the pi'oximal phalanx of the medius. In the Ehino- 

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

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

 minimus, the annularis going to the proximal phalanx in (67), i^nd 

 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 

 (74, 78), it is inserted into the annularis and minimus (74, 77) or 

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

 posterior interosseous, " " 



Extensor carpi idnaris- also called posterior' uhiaris, alnaris 

 externus, &nd Jlexor metacarpii extermis.—'Th\s muscle in ■ the 

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

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

 before which it often joins the tendon of the flexor carpi ulnaris ; 

 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, 3), but in the 8uidie (4, 5, 7, 11, 13, 14) 

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



