1903.] THE MUSCLES OF THE UXGULATA. 277 



Extensor proprius hallucis. — This muscle is often described in 

 Ungulates, but, we think, without any real reason. As the 

 hallux and often the fibula are suppressed, the muscle called 

 extensor proprius hallucis is a slip of the extensor longus 

 digitorum passing to the index or medius digit. Unless the 

 authors who use the name have good grounds for thinking that 

 this is really a displaced muscle of the hallux, it seems a needless 

 complication to retain the name in the Ungulata. 



Extensor longvs digitorum. — In the Hippopotamidse (1,3) and 

 Suidas (4, 7, 10, 11, 12, 13, 14) this muscle is inserted into all 

 four toes, and its origin is from the front of the external condyle 

 of the femur with the tibialis anticus. Meckel (VII.) denies 

 that it has a femoral origin in the Pig, but his was clearly an 

 exceptional case. In the other Artiodactyla the origin is always 

 femoral and the insertion into both toes. An intei'esting point 

 about this muscle in the Ox (40), Sheep (46), Duiker-bok (54), 

 Harnessed Antelope (55), Chevrotain (20), and Camel (17) is 

 that there is an insertion into the middle phalanx of the medius 

 digit as well as into the terminal of the medius and annularis. 

 A more careful examination of the muscle in the other Artio- 

 dactyles would possibly show that this is a constant arrangement, 

 In the Tapirid^ (59, 61, 62) and Rhinocerotidse the origin is 

 femoral and the insertion into all three toes. In the Equidse 

 (63, 65) the origin is also femoral and the insertion into the 

 middle and terminal phalanges of the single digit (medius). 

 Among the Subungulata the origin is femoral in Hyrax (74, 75), 

 though Meckel (VII.) says that it is tibial ; its insertion is into 

 all the digits. In the Elephant (81, 84, 85) the origin is certainly 

 tibial and the insertion into the 2nd, 3rd, 4th and 5th digits. 

 Both Patersonand Dun (85) and Miall and Greenwood (81) notice 

 that insertions are given to some of the proximal as well as the 

 distal phalanges, though which digits have slips to these phalanges 

 varies in different individuals as well as on opposite sides of the 

 same individual. The nerve- supply is the anterior crural. 

 Summing up, it may be said that the origin of this muscle in the 

 Ungulata is always femoral except in the Elephant. 



Extensor brevis digitorum. — This muscle is always present and 

 has the usual origin from the front of the upper surface of the 

 calcaneum. In the Hippopotamus (1, 3) it is inserted into 

 the index, medius, and annularis digits. In the Suidse (4, 5, 10, 

 11, 14) it usually goes to the medius and annularis only, but it 

 may send a slip which joins the tendon of the extensor longus 

 digitorum on the dorsum of the foot. 



In the Tapiridse (61, 62) the muscle is very large and is 

 inserted into all three toes. Murie (XVII.) notices that the slip 

 to the medius is inserted into the proximal phalanx. In the 

 Equidse (63, 65) there is only one insertion into the extensor longus 

 as in the Ruminants. In the Rhinoceros, Haughton (XXI.) 

 only found a tendon for the medius toe. Among the Subungulata, 

 Hyrax may have three tendons for the proximal phalanges 



