CRANIAL NERVES OF CAECILIANS 511 



In the adult condition of Herpele the two divisions arise from 

 the brain by a common root which soon divides. A shorter lat- 

 eral maxillo-mandibular division runs mimediately into the Gas- 

 serian ganglion (figs. 25, 26, Vrmd-mx.). The latter is somewhat 

 triangular in cross-section, and lies in a part of a long recess in the 

 cranial wall which is occupied by the combined ganglia of the 

 fifth and seventh nerves. The cavity is bounded posteriorly by 

 the pterygoquadrate bone ventrally and laterally and by the 

 alisphenoid region of the basal bone dorsally (figs. 25 to 29). 

 Anteriorly the levator quadrati, temporal, and masseter muscles 

 and the parietal bone have a share in its boundary (figs. 22 to 

 24). Posteriorly the Gasserian ganglion is in contact with the 

 facial ganglion (figs. 27, 29, gg., gen.), but distinct from it. An- 

 teriorly it is slightly in contact with the profundus ganglion (figs. 

 23, 24, 29). Directly opposite the point of entrance of the root 

 into the ganglion the trunk of the ramus mandibularis, composed 

 of motor and somatic sensory fibers (figs. 25, 26, 44, vid.) 

 passes out laterally. A section through the ganglion at this 

 level shows, at the medial ventral border of the ganglion, the 

 ramus palatinus of the seventh nerve (pal.), with which fibers 

 from the Gasserian ganglion are associated. A little farther 

 ventromedially is the abducens nerve {VI). In the ganglion and 

 a little dorsal to its middle is a small darkly colored strand of 

 fibers (os.) derived, as will be described later, from the facial 

 nerve. With it are apparently associated fibers from the fifth 

 nerve. At the posterior dorsal border of the Gasserian ganglion 

 this small strand has a small ganghon (figs. 27, 44, gild.), and its 

 position seems to correspond to that of a dorsal lateral line gang- 

 lion in the larval stage. Toward the posterior part of the Gas- 

 serian ganglion there leaves its lateral border a small band of 

 non-medullated fibers (fig. 27, sy.V), a part of the sympathetic 

 chain, the course of which will be traced later. 



The ophthalmic division of the root of the. trigeminal nerve 

 passes anteriorly at the lateral border of the brain (figs. 25, 26, 

 Vrop.) and enters its ganglion at the anteroventral border of 

 the Gasserian ganglion (fig. 24, gop.). For a short distance the 

 two gangha are in contact, but not confluent. At the lateral 



