The transrersalis cert.-leis is closely adherent to the trachelo-mastoideus. Separated from the former, there is in some ruminants a muscle, which— corresponding with that por tion of the sacro-lumbalis in man, called the cervicalis descendens—stretch es from between the transverse apophyses of several of the lower cervical vertebrm to the oblique and transverse processes of certain of the dorsal segments. Merkel alludes to thts peculiarity in the Ilorse.
The scateni muscles, three in number on either side, are very long and powerfully developed in the Camel and Giraffe, presenting in the latter, according to Prof. Owen, four distinct masses, which take their origin "front the fourth, fifth, sixth, and seventh cervical vertebrm, and are inserted into the manubrium sterni and first rib." In the Sheep the fleshy bundles are very small ; they also arise from the lowermost four cervical vertebrm ; but in the Camel they are connected to all the bones of the neck, except the dentata, the posterior scalenus being particularly short, and only attached to the last.
The longus colli and recti have a similar disposition to those of Man, The former is divided into a superficial and deep portion, the latter division extending as far back as the third vertebrm of the thorax. In the Camel this muscle exhibits an inerease of develop ment proportionate with the elongated neck, its posterior attachment commencing at the body of the fourth dorsal segment. The rectus capitis antimis, major and minor, are comparatively insignificant in all ruminants and solipeds.
The muscular arrangements at the fore-part of the neck present many points of interest; for example,— the sterno-cleido-mastoideus of anthropotomists is represented in the ma jority of mammifers by two distinct muscles. The first of these, the sterno-mastoideus or maxillaris, is a slender fleshy band which divides near the middle and fore-part of the neck into two portions, one being inserted a little in front of the angle of the lower jaw, and the other becoming attached to the mastoid process. In the Sheep the anterior tendon extends as far forward as the zygo matic arch, and immediately behind the jaw the muscle is united to the deltoides, beneath which it is also connected to the rectus capitis antic= major by an intervening ten don. In the Camels this muscle is fleshy throughout its entire extent, and at the lower part is joined to its fellow of the opposite side ; superiorly, its tendons are fixed— one to the mastoid process, and another to the maxilla over the region of the submaxillary gland. The characters and position of this muscle are precisely similar in the Giraffe. The situation of the cleido-mastoideus has been already indicated in the description of the tripartite deltoides.
Hyoid apparatus. — Before noticing the muscles connected with the os hyoides it is necessary to direct attention to its osseous framework.
The hyoid bone is made up of a congeries of ossicles more or less consolidated, having relation to totally different parts of the ske leton, but here associated together for the threefold purpose of supporting the tongue and larynx, and affording a point d'appui for the muscles destined to act upon these organs. In the ruminant, as in Solipeda, nine distinct elements may be recognised, arranged in four pairs, the ninth piece being represented by the body or basi-hyal bone. Fig. 351. indicates the relation of these parts in the sheep. Com mencing from above, the first pair—the styloid bones — or stylo-hyals (1, 1) are seen to have an enormous longitudinal development, being also somewhat hammer-shaped and com pressed laterally, to favour muscular ment. Their peculiar figure is due to the presence of two apophyses at the temporal extremity (aa, bb) and it is by the superior process that the bony chain is connected with the cranium. In the Horse these bones are proportionally longer, but they are shorter in the Camelidte than in the typical ruminants. In Man the styloid processes of the temporal are homologous with the stylo-hyals. The second pair or epi-hyals (2,2) are intercalated between the first and third series of ossicles, and complete a right angle, formed by- the relatively horizontal and vertical position of those bones ; they have an insignificant ap pearance in most of the genera, but attain in the Camels a considerable size. More than two nodules are sometimes present. The epi-hyals are most conspicuous in the carni vorous mammifers, but in the human subject are merely represented by two long liga mentous bands, which in a few instances have been found ossified. The third pair or cerato hyals (3, 3) have a nearly vertical position vvhen the head is raised, and they constitute with the epi-hyals, the lesser cornua which in Man are feebly indicated, being recognised only by two small pisiform nodules moveably articulated to the body of the hyoid, and forming, as in the present instance, a right angle with the greater cornua. In the typical
ruminants these elements are larger than the epi-hyals, but in the Dromedary, according to Duvernoy, this character is reversed. The body of the hyoid or basi-hyal (4), of a tri angular form, is placed below the cerato hyals and anterior to the greater cornua, the four ossicles of which they together consist, being articulated to the extremities of its lateral apophyses on either side. There is generally a slight bulging at the anterior and middle part, indicative of the tendency to antero-posterior elongation, which feature becomes very manifest in other vertebrata, and more particularly in birds ; it is to this point that an additional element — the true lingual bone or glosso-hyal — is connected, in many of the avian and piscine families, traces of it also appearing in Solipeda and other quadrupeds ; it is remarkably large in the Bear. In Camelidm the basi-hyal presents no anterior protuberance. The fourth pair or thyro-hyals — hypo-branchials of fishes and amphibia—(5, .5) represent the greater cornua of the anthropotomist, but in certain rnam mifers, as in the fatuity under consideration, their extent of development is subordinate to that of the lesser horns. In birds, on the other hand, the length of the thyro-hyals is extreme, the lesser cornua being either rudi mentary, or altogether absent.* The muscles proper to the hyoid chain of bones present many interesting modifications. The sterno-hyoids and sterno-thyroids (which in Man and mammifera generally, remain distinct throughout their entire extent), are united below in the majority of ruminants, their com mon band of origin dividing near the middle of the neck, the larger division being connected to the hyoid bone. Meckel states that the sterno-hyoid is entirely absent in the Camel, and Duvernoy remarks the same peculiarity in the Sheep ; but Gurlt figures the upper part of it in the latter animal and in the Ox. A muscle analogous to the onzo-hyoid presents a remarkable difference of origin, relatively, in the typical ruminants, the Camel and the Giraffe. In the Sheep it originates, according to Meckel, in the form of a muscular band of considerable dimensions, which is given off' by- the rectus capitis anticus major, and leaves that muscle at a point corresponding to the third cervical vertebra to be inserted into the hyoid immediately behind the attachment of the thyro-hyoid muscle. Its relation in the Giraffe will be reverted to presently. In the Camel the disposition of this structure is ex tremely complicated. From the researches of Meckel we learn that it arises from the anterior division of the transverse process of the fourth cervical vertebra, and is confounded near its commencement with the lowermost bundle of the straight anterior muscle of the head ; it subsequently divides into three por tions, the first becoming inserted into the lower lip, the second going to the posterior cornua of the hyoid, and the third attaching itself to the lower jaw, upon which it acts as a powerful depressor. Professor Goodsir has remarked to us that an anomaly analogous to this latter distribution is sometimes seen in the human subject. The stylo-hyoid, which is absent in certain Carnivora, its place being sup plied by a narrow muscle termed the ceratoido laterahs, is present in the Ruminantia, where the latter muscle appears as a prolongation of the stylo-hyoid rather than as a:distinct muscle. The first of these two muscles — regarding them as such — proceeds by a long tendon from the posterior and inferior apophysis of the styloid bone, to be attached below to the base of the thyroid cornua ; the ceratoido Lateran.: also descends obliquely from the lesser horn to the greater. In both the above named families and in the Pachydermata there is likewise a special muscle termed the masto styloid ; it is short and triangular, and, arising from the mastoid process of the temporal bone, becomes inserted into the inferior apo physis of the hammer-shaped extremity of the stylo-hyal element or styloid bone, immediately above the origin of the tendon of the stylo hyoid muscle. The mylo-hyoid is distinctly double, the anterior bundle having an extended longitudinal development, while the posterior division is short, and has its fibres directed transversely outward. The genio-hyoids of either side are incorporated at the middle line.