7<5 ANATOMY OF A CHELONIAN. 



boring muscles, and a somewhat larger one, which 

 passes forward and enters the temporal muscles near the 

 articulation of the mandible. 



a. The remaining principal portion of the nerve 

 then runs downward and forward to the slit in 

 the upper side of the ramus of the lower jaw 

 (53), and divides into two branches, which en- 

 ter it. 



b. The larger anterior branch runs forward in 

 the mandible, giving off branches in it, and 

 appears again on its inner side, just above 

 Meckel's cartilage (54, a), where that first 

 comes into view on the mesial side of the 

 ramus of the mandible. It is then distributed 

 to parts in the floor of the mouth. 



c. The posterior division of the inferior maxillary- 

 nerve runs down nearly vertically through the 

 ramus of the mandible and reappears on its 

 inner side, near the lower border of the bone, 

 through a special foramen (53), and is then 

 distributed to the neighboring soft parts. 



192. Trace back the sixth nerve, from the part al- 

 ready seen in the orbit till it enters the basisphenoid, 

 and then follow it, by breaking away the bone with 

 great care. The nerve, while in its bony channel, will 

 be found to receive a branch from the Gasserian gan- 

 glion, which passes in through a minute bony canal, and 

 a small ganglion is placed at the point of junction. From 

 this ganglion three branches arise. Trace them out. 



193. Taking now a fresh terrapin, chloroform and 

 open it in the manner already described (77). 



