42 bulletin: museum of comparative zoology. 



shaped, having its origin from the parietal ridge and neck fascia along 

 an irregular line which anteriorly lies near the median plane, but 

 posteriorly assumes a more lateral position (Fig. G). All the fibers 

 converge to the articulare of the lower jaw, where most of them are 

 inserted at the extreme posterior point by means of a ligamentous 

 attachment. A thin band {dep. vidS), however, passes around to the 

 ventral side and a little farther cephalad finds attachment in the fascia 

 which also serves for the posterior fibers of m. mylohyoides (Figs. 

 F and J). The anterior border of this muscle (Plate 3, fig. 7, dep. md.) 

 forms the posterior border of the external auditory meatus and is the 

 thickest and strongest part of the muscle. This portion is roughly 

 separable from the sheet-like part behind it and has a firmer origin in 

 the skull, the thinner portions behind arising from the neck. The 

 tympanic chamber extends backward underneath this muscle (Plates 

 6, 7, figs. 19-24). 



The innervation of this muscle is wholly from motor VII, which 

 supplies it by two main branches (Fig. J). 



Versluys ('98, p. 285) refers to the thinner posterior portion as 

 occurring in many Lacertilia. It corresponds to the "superficial" 

 portion and Ca md of Ruge ('97, p. 326-331) for Varanus. The 

 thicker part is the " Hauptportion " of Versluys. 



M. episterno-cleido-mastoideus (Versluys) capiti-cleido-episternalis, 

 (Watkinson). This muscle (c'sfn-clei-mast.), which extends from the 

 skull, having its origin underneath the main part of the m. depressor 

 mandibulae, passes caudo-ventrad to be inserted on the sternum (Fig. 

 G). It forms a thickened ventral border to the cucullaris muscle, 

 next to be described, and has the same innervation (Plate 7, fig. 24). 



M. capiti-dorso-clavicidaris (trapezius, or cucullaris). The fibers 

 of this muscle (Fig. G, cap. d'clav.), have the same direction as 

 the preceding, but both origin and insertion are different. It is an 

 extremely thin sheet of fibers having origin underneath the thin 

 posterior part of the m. depressor mandibulae and being inserted on the 

 pectoral girdle. The line of origin extends well back past the level of 

 insertion, so that the most posterior fibers are directed forward. It 

 does not form a continuous sheet, but between the successive bundles 

 are spaces which leave exposed the underlying lymph sac (Plate 7, 

 fig. 24, sac. cn'lym.). These spaces are not indicated in figure G. 



The innervation of the two foregoing muscles is from two or more 

 spinal nerves, (Plates 2 and 3, figs. 4, 6, spi. v. 3) the first muscle being 

 supplied wholly from the motor part of the third spinal nerve, which 

 comes out to the muscle as a mixed lateral ramus. The sensory part 



