1903.] THE MUSCLES OF THE UNGULATA. 285 



is small and is visually only inserted into the atlas, though in the 

 Ox (36) it reaches the axis as well. It is absent in the Camel 

 (15, 18) and Giraffe (33), though present in the Ohevrotain (20). 



In the Perissodactyla, judging from the Horse (63, 65, 67) and 

 Tapir (62), it is specially strong, and in the latter animal is 

 inserted into the six anterior cervical transverse processes. Among 

 the Subungulata it is present in Hyrax (74, 75), but absent in 

 the Elephant (81). 



Erector spince.—HYie outer portion of this muscle, which in 

 Man is composed of the sacro-lumbalis, accessorius, and cervicalis 

 ascendens, is not well developed in Ungulates except the Sub- 

 ungulata (Hyrax and Elephant) ; the sacral origin is very feeble 

 and is represented only by a delicate fibrous band rising from 

 the common origin on the dorsal surface of the sacrum. The 

 accessorius is the best developed part, and rises from the hinder 

 ribs near their angles to be inserted into the same place on the 

 anterior ribs. The cervicalis ascendens is represented only by 

 one slip going to the transverse process of the 7th cervical 

 vertebra. Although these muscles are feeble they are usually 

 quite clearly marked off from the longissimus dorsi. In the Horse 

 the accessorius and sacro-lumbalis are less well developed than 

 in the Artiodactyla, and, according to Chauveau (II.), are in- 

 separable from the longissimus, though other authors were easily 

 able to distinguish the two. 



The Longissimus dorsi is always well developed and has an 

 external series of attachments just internal to the angles of the 

 ribs, and an internal to the thoracic transverse processes ; this 

 internal series of attachments is continued up into the neck as 

 the transversalis colli, trachelo-mastoid, and complexus. 



While the spinalis colli is very strong, the spinalis dorsi is less 

 well developed but still quite distinguishable. The semispinalis 

 is well developed, especially in the neck. 



The Transversalis colli is always present, and is inserted by a 

 series of slips into the first five cervical vertebrae. 



The Trachelo-mastoid (transversalis capitis) is, as usual, a con- 

 tinuation vipward of the longissimus dorsi and is inserted into 

 the paramastoid process of the temporal bone ; it is closely con- 

 nected with the transversalis colli. Lesbres (Y.) says that it 

 divides at its insertion, one part being attached to the skull and 

 the other into the transverse process of the atlas. From our 

 own dissections we feel sure that Lesbres has included a slip 

 of the transversalis colli in his description. In the Ohevrotain, 

 Kinberg (X.) says the muscle is absent, but we found it in our 

 specimen (21). In the Hyrax (75) we noticed that the muscle 

 continued to rise in the neck from the articular processes of the 

 cervical vertebree. 



Complexus. — This muscle rises from the transverse processes of 

 the anterior thoracic vex-tebrse, varying from the 3rd to the 10th, 

 as well as fi'om the articular processes of the posterior cervical 

 vertebr.T ; it is inserted into the skull just below the occipital 



