1901.] THE MUSCLES OF THE UNGULATA. 675 



Among the Pei'issodactyla the Tapir (52, 53, 54, 55) has a 

 masseteric insertion into the angle of the mantlible, and Lesbres 

 (V.) also found a basioccipital insertion, though in our specimen 

 we failed to find this (54), 



In the Equidae (56, 58, 59, 61) the masseteric attachment is 

 also into the posterior border of the ramus just above the angle, but 

 there is no basioccipital nor paramastoid (59) insertion. The two 

 sterno-mastoids of opposite sides blend in the mid-line oF the 

 posterior part of the neck. In all the above-mentioned families 

 where it is not specially mentioned, the cleido-mastoid rises from 

 the clavicular tendinous intersection in the cephalo-humeral, and 

 is inserted into the paramastoid process deep to the insertion of 

 the sterno-mastoid. 



In the Procaviidae (67, 68) the sterno-mastoid, sterno-masseteric, 

 and cleido-mastoid elements are present, but the cleido-mastoid is 

 attached to the occipital crest instead of the paramastoid process, 

 and the masseteric portion is a huge muscular mass rising from 

 the manubrium and its fellow of the opposite side in the mid- 

 ventral line of the caudal half of the neck, and being inserted into 

 the angle of the mandible and the fascia over the uiasseter. The 

 sterno-mastoid element to the paramastoid process is very small. 



The Elephantidse are remarkable for having two masseteric 

 insertions (74, 76, 77), one into the posterior part of the zygoma, 

 and the other into the body of the mandible just in front of the 

 insertion of the digastric. The latter part is a separate muscle in 

 its whole extent, and according to Anderson (XXVII.) rises by 

 three heads, two from the first rib and one from the sternum. 

 The cleido-mastoid has the usual ungulate attachments ; but in 

 Cuvier and Laurillard's plate (I.) seems to send a slip to the basi- 

 occipital. 



Prom the above it will be seen that the masseteric portion of 

 the sterno-mastoid is a very characteristic ungulate arrangement, 

 which is wanting in the Suidse and in the Sheep, and, if present, 

 is only feebly developed in the Hippopotamus. It varies in its 

 exact attachment in different families; but its presence in Hyrax 

 is of interest as pointing to the ungulate affinities of that animal. 



The nerve-supply of the sterno-mastoid, sterno-masseteric, and 

 cleido-mastoid portions of the muscle is the spinal accessory and 

 cervical nerves in the Sheep, Pig, Chevrotain, and Antelope. 



Omo - trachelian Muscle. — This muscle seems fairly constant 

 throughout the Order, and runs from the transverse process of the 

 atlas to the acromial end of the spine of the scapula, as well as to 

 the fascia over the infraspinatus and scapular part of the deltoid. 

 It becomes superficial by passing between the occipital and cervical 

 portions of the trapezius, which as a rule are veiy distinct. Many 

 authors describe the omo-trachelian as fusing posteriorly with the 

 cephalo-humeral, and in two or three of our own dissections we 

 have thought that it ended in this way ; but more careful dissection 

 enabled us to trace the muscle to the region where the acromial 

 process ought to be, so tliat although we shall divide the material 



