102 ■ THE OSTEOLOGY AND MYOLOGY 



the neck as the "transversalis cervicis." This forms in the neck, and along the upper part 

 of the thorax, a tolerably distinct flattened muscle, divided into slips that continue below 

 as longissimus, and are inserted above into the transverse processes of the third — seventh 

 cervical vertebrae, by as many separate tendons. It separates the lower part of the trachelo- 

 mastoid from the upper part of the levator anguli scapulae. The spinalis, likewise running 

 up the neck, passes inside the biventer and complexus, and terminates in a series of stout, 

 fleshy slips lying upon the sides of the spinous processes of the vertebrae, and inserted near 

 then- apices, as high up as the thu'd cervical — where the greater rectus and obliquus capitis 

 begin. 



Muscles of the Tail. 



The muscles of this part, as usual in prehensile-tailed animals, are large and numerous, 

 and especially notable for the extent of their attachments to the pelvis, and sacral and lum- 

 bar portions of the spine. They form an elongated cone, diminishing rapidly just behind 

 the pelvis, and thence tapering regularly and very gradually to the tip of the tail. For a 

 little distance beyond the root of the tail, all the muscles are perfectly distinct, and most of 

 them are directly continuous ; in the rest of their course, those that extend the entire 

 length of the tail become more or less blended, diminish in size both by the actual decrease 

 of the volume of muscle and by the giving out of fasciculi to be inserted by tendons at 

 various points, and lose continuity in a measure by being firmly attached to the salient 

 points at the extremity of each vertebra, so that, in effect, they are a succession of short 

 muscles. Certain tendons, however, run the entire length of the tail without intermediate 

 insertion ; these are described below. 



The structure and disposition of the flexing set of muscles is the same as that of the 

 extending ; but in bulk, and consequently in power, it greatly preponderates over the lat- 

 ter. This confers the grasping power of the tail ; while the extent of pelvic and vertebral 

 attachments of both sets of muscles is sufficient to snpport the weight of the hanging body 

 without inconvenience. Although the volume of muscle toward the tip of the tail is incon- 

 siderable, the animal can suspend itself from a suitable object, as a twig, by only wrapping 

 around it an inch or two of its tail. The large muscles of the base of the tail are in 

 this case really brought into play by the action of their long tendons. Action of the 

 flexor muscles is favored and increased by the series of V-shaped bones that serve as so 

 many points cVappui; and after the spinous, transverse and articular processes cease, the 

 quadrangular extremities of the vertebrae replace these processes as points of muscular 

 attachment and action. 



Besides the caudal muscles proper, others take oi'igin from the coccygeal vertebrae. 

 These are: — the posterior part of the glutaeus maximus, the " femoro-coccygeus" (when this 

 exists as distinct from the latter), the cruro-coccygeus, the pyriformis (if the disputed ver- 

 tebra be really caudal), and the levator recti. These are all considered in other connections. 



On stripping off the thick, squamous, reticulated skin, the tail is seen to be encased in an 

 uninterrupted sheath of very dense fascia, comparable for thickness and strength with 

 the ordinary fasciae of the body, much as the fascia lata of the human subject compares 

 with similar structures in other parts of the body. This fibrous sheath gives off septa 

 from its under surface that penetrate between, and separate, the different bundles of muscle, 



