82 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
the same nerve of the opposite side (Plate 2, fig. 5, an’stm. lar.). The 
chiasma is not a complete one; hence each muscle of the larynx is 
stimulated through motor fibers from both sides of the brain. ie 
The muscles of the larynx consist of an outer longitudinal clea 
and an inner transverse (constrictor) pair, (Plate 4, fig. 11, lar. lg. and — 
co’st. lar.). They are innervated exclusively from the coarse fibered 
elements carried in the pharyngo-laryngeus IX and X. Attention 
is called to the fact that this motor innervation may be from IX, from 
X, or from both. There is no possibility of determining in Anolis, 
except experimentally, which nerve has given up its fibers to the cerato- 
hyoideus muscle. If dissections may be trusted on this point, the 
condition as described by Watkinson (:06) in Varanus would support 
the view that the fibers innervating the cerato-hyoideus (hyoglossus) 
muscle are from IX. In Varanus IX does not anastomose with XII 
and does not appear to combine with X in a manner corresponding 
to the condition in Anolis. In the former the nerve described as 1X 
innervates the cerato-hyoideus muscle as it crosses the ventral face 
of that muscle. There are more proximal anastomoses, however, 
making possible some combination of the fibers of IX and X as in 
Anolis; so, in the absence of microscopic observation, any conclusion 
must be tentative. 
The laryngeal anastomosis is quite generally mentioned where the 
innervation of this region is described in higher vertebrates. ‘The 
‘ramus recurrens X is usually described as entering into this “sling” 
and joining in the motor innervation. In Anolis, however, the ramus 
recurrens takes no part in the sling, although the terminal ramus of 
this nerve passes through the longitudinal laryngeal muscle (Plate 2, 
Fig. 5, lar. lg.) to reach the dorsal free edge of the laryngeal cartilage, 
where its fibers may be seen turning in to innervate the epithe iu Do 
of the larynx (Plate 2, fig. 5, rer. X). ee 
(3) Ramus visceralis (vse. X). This is the name given the main 
trunk of the vagus after the superior laryngeal nerve is given off. 
It is a fine-fibered bundle, which closely resembles the main sympa- 
thetic, with which it has a parallel course across the dorsal si of 
the thymus gland. It bears the large trunk ganglion (gn. nd.) i m 
its course and then gives off to the mucous membrane sensory 
branches, which correspond to the posterior laryngeal, and also the 
ramus recurrens X. In the series plotted the sections are not 
