The Cranial Nerves of Varanus bivittatus. 467 
is formed with the end branch of glossopharyngeus and the united 
fibres innervate the museles of the larynx. 
e) Ramus laryngo-pharyngeus arises in a common stem witlı 
ramus recurrens, as above described, and spreads with many fibres 
over the membrane of the pharynx in its posterior region. 
f) Ramus communicans posterior cum nervo sympathico occurs 
in the anterior region of the lungs. The branch runs from the 
vagus stem laterally and anteriorally over the ventral surface of 
the lung and joins the main thoraeie stem of sympathieus in the 
region of the brachial plexus. 
g) Rami cardiaci arise just before the pulmonary branches, that 
is, where the tracheal tube divides into the bronchii and the nerve 
bends laterally with these to innervate the lungs. There are two 
main cardiae nerves on each side and these follow the walls of the 
two anterior arteries to the wall of the heart itself which they enter 
close to the origin of the respective arteries. 
h) Rami pulmonales comprise te main end branches of vagus 
and follow the branchings of the bronchii with many fine fibres to 
the various parts of the lungs. 
i) Rami gastriei arise from the larger of the rami pulmonales 
which continue through the posterior portion of the Jungs. An an- 
terior and a posterior pair from each side unite and pass through 
the mesentary in the stomach region. They form a plexus with 
the sympathico-spinal nerves in the mesentary of the stomach. 
XI. Nervus accessorius arises as a number of fine nerves 
from the anterior cervical region. These unite into a single stem 
which enters the skull through the foramen magnum. Here it 
unites with the stem of vagus and passes with the latter through 
a special canal to the cervical region. A branch given off from 
the latter nerve as soon as it emerges from its own foramen, prob- 
ably comprises part, if not all, of the accessorious elements thus 
received, but this cannot be ascertained by maeroscopieal examination. 
This branch is called »ramus externus nervi vagi« and innervates 
musc. sterno-cleido-hyoideus near its origin from the skull. This 
muscle also receives innervation from the third cervical nerve, the 
end fibres of which form an intricate sling with those of ramus 
externus. 
XII. Nervus hypoglossus arises partly from the eranial and 
partly from the cervical region of the central nervous system. The 
cranial element consists of three roots arising from the lateral wall 
