42 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
shaped, having its origin from the parietal ridge and neck fascia along 
an irregular line which anteriorly les near the median plane, but 
posteriorly assumes a more lateral position (Fig. @). 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. md.'), 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. 
Fand 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 C, 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 (e’stn-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. cayiti-dorso-clavicularis (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. en’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 8, 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 
