IOWA ACADEMY OF SCIENCES. 101 
nerve ganglion, then turning ventrally and anteriorly 
divides into two branches, one of which unites with a 
branch of the vagus as above described, the other passes 
anteriorly into the connective tissue ventral to the thymus 
gland. The first spinal nerve does not share in the 
brachial plexus. The brachial plexus is formed from 
the main trunks of the second and third spinal nerves. I 
did not trace the branches of the brachial plexus to their 
final distribution. 
EXPLANATION OF PLATE. 
Projection of theVIIth., IXth. and Xth. cranial, the hypoglossal and 
the anterior spinal nerves of Amphiuma seen from the right side. 
REFERENCE FIGURES AND LETTERS. 
J . Origin of Jacobson’s commissure from vagus ganglion. 
2. Supratemporalis (?) nerve. 
3. Glossopharyngeal— branchial trunk. 
4. Second branchial nerve. 
5. Third branchial nerve. 
6. Ramus lateralis superior of vagus. 
7. Ramus lateralis medius of vagus. 
8. Ramus inferior of vagus, 
aa, branches of auditory nerve. 
AfBr, nerve to inner border of afferent branchial vessel. 
afbr, nerve to outer border of afferent branchial vessel. 
AG , Auditory-facial ganglion . 
Alv , alveolaris branch of facial nerve. 
Br, brachial nerve. 
Brpl , brachial plexus. 
Dir, branch of vagus to dorsotrachealis muscle. 
Gl, glossopharyngeal nerve trunk. 
Hm , hyomandibular branch of facial nerve. 
Htna, hyomandibularis accessorius branch of facial nerve. 
Hy , hypoglossal nerve. 
Jc, Jacobson’s commissure. 
Mfe , maxillaris facialis externus branch of facial nerve. 
Pal , palatine branch of facial nerve. 
RiX , ramus intestinalis of vagus nerve. 
RIVII , ramus lateralis posterior of facial nerve. 
RliX , ramus lateralis inferior of vagus nerve. 
RlmX , ramus lateralis medius of vagus nerve. 
R/sX, ramus lateralis superior of vagus nerve. 
