280 MESSRS. B. C. A. WINKLE AXD F. G. PARSONS OX [NoV. 3, 



Posterior Tibial Region. 



Gastrocnemius. — The two heads of this muscle rise, as usual, 

 from just above the condyles of the femur ; the inner is generally 

 more extensive in its origin than the external and often extends 

 over a considerable portion of tlie popliteal surface of the femur. 

 One of the most notable points in this muscle in the Ungulata is 

 the absence of fabellfe in its origins, The only member of the 

 order in which we have found fabellse is the Hyrax, and in it 

 only the outer one was present. The tendo Achillis shows the 

 characteristic rope-like twisting previously described by one of us 

 (Journ. Anat. vol. xxviii. p. 414) very well, and in some animals, 

 e. g. the Elephant (79) and Musk-Deer (31), the tendons remain 

 separate as far as the calcaneum. In the Chevrotain, Kinberg 

 (X.) describes the outer head as having an anterior and posterior 

 origin. In the Hippopotamus, Gratiolet and Alix (III.) say that 

 the origins are continued down to the tibia. The expansions 

 from the thigh-muscles forming a sheath for the gastrocnemius 

 tendon have already been described. The nerve-supply is always 

 the internal popliteal. 



Soleus. — In the Hippopotamidee (1, 3) and Suidas (4, 6, 9, 11, 

 12, 14) this is either wanting or, more probably, has shifted its 

 origin upward to the external condyle of the femur and is fused 

 with the external head of the gastrocnemius. In Ouvier and 

 Ijaurillard's Peccary (13), however, its origin is drawn rising 

 from the surface of the peroneus quarti digiti. In the Tragulidse 

 (20, 22) the muscle is distinct, and in our specimen (22) rose 

 from the middle third of the fibula. In the Cervidse (29, 30) it 

 rises from the external condyle, but is a distinct, though small, 

 muscle. In the Bovidse (40, 48, 54, 55) it usually rises from 

 the rudimentary head of the fibula and joins the outer head of 

 the gastrocnemius. In the Tapiridfe (61, 62) it is condylar and 

 very small. Turner (XVI.) failed to find it at all. In the 

 Equidas (63, 64, 65) it rises from the external tuberosity of the 

 tibia. We have no record of it in the Rhinocerotidse. 



In the Procaviidfe (74, 75) it comes from the head of the fibula 

 and is fairly well developed. In the Elephantidse (74, 77, 79) it 

 is also well developed, rises from the head of the fibula and is 

 inserted separately into the calcaneum. 



From the foregoing it will be seen that this muscle in the 

 Ungulata is subject to a good deal of variation, but in all except 

 the Subungulata is feebly developed. In the Hippopotamidse, 

 Suidee, Cervidse, and Tapiridse its origin is usually shifted up to 

 the external condyle, while in the other families it rises either 

 from the fibula or from the adjacent external tuberosity of the 

 tibia. Its nerve-supply is the internal popliteal. 



Plantaris. — This muscle is alw^ays present in the Ungulata. 

 In the Hippopotamus (1) it has a very large muscular belly rising 

 from above the external condyle of the femur ; this tendon in the 

 sole has a few fleshy fibres on its deep surface and is the only 



