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Show 1903.] THE MUSCLES OF THE UNGULATA. 285 is small and is usually 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 Chevrotain (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.-The outer portion of this muscle, which in M a n is composed of the sacro-lumbalis, accessorius, and cervicalis ascendens, is not well developed in Ungulates except the Subungulata (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 inseparable 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 continuation upward of the longissimus dorsi and is inserted into the paramastoid process of the temporal bone; it is closely connected with the transversalis colli. Lesbres (V.) 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 Chevrotain, 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 vertebrae. Complexus.-This muscle rises from the transverse processes of the anterior thoracic vertebrae, varying from the 3rd to the 10th, as well as from the articular processes of the posterior cervical vertebra?; it is inserted into the skull just below the occipital |