336 H. W. NORMS AND SALLY P. HUGHES 



small branches of the latter. Anteriorly it is distributed to the 

 skin of the dorsal side of the head, dorsal and anterior to the 

 eye (fig. 23). 



In those amphibians in which somatic sensory fibers are asso- 

 ciated with the r. oph. spf. VII, they occur in a diffuse arrange- 

 ment, and are given off from the ganglion or near the base of 

 the supraorbital trunk, in a fashion suggestive of the mode of 

 occurrence in Squalus. 



5. The ramus maxillaris V 



This nerve arises from the smaller extracranial portion of the 

 gasserian ganglion as a large mass of fibers that joins the ramus 

 buccalis VII to form the infraorbital trunk. At first somewhat 

 triangular in cross-section (figs. 7 to 10 and 20, mx.) on the mesial 

 border of the infraorbital trunk, farther anteriorly it becomes a 

 flattened band curved around the ventromesial border (figs. 5, 

 6, 21, and 22). Still farther anteriorly it covers the infraorbital 

 trunk dorsally, mesially, and ventrally (fig. 24), thence sepa- 

 rating into a dorsal, a mesial, and a ventral band. With the 

 giving off of certain small branches to the ventral surface of the 

 head anterior to the mouth, some of which run posteriorly from 

 their origin from the main nerve, the ramus maxillaris together 

 with the ramus buccalis divides into three groups of nerves, the 

 largest mesial one running anteriorly and supplying the ventral 

 surface of the snout mesially and anterior to the level of the 

 eyes. The other two divisions supply the ventrolateral epithe- 

 lium of the snout. One of the small posteriorly directed branches 

 runs far back at the lateral angle of the mouth, terminating at 

 the lateral border of the oral epithelium between Meckel's car- 

 tilage and the palatoquadrate bar (fig. 35, mxph.). This small 

 nerve evidently corresponds to Cole's ('9G) pharyngeal branch of 

 the ramus maxillaris in Chimaera. 



The association of the maxillaris with the buccalis is every- 

 where very intimate, even into the small branches. The large 

 nerves commonly break up into their smaller divisions long be- 

 fore the latter leave the vicinity of the main nerves (figs. 1 to 4 

 and 34). In, consequence their representation in the illustrations 

 is somewhat diagrammatic. 



