CRANIAL NERVES OF CAECILIANS 523 



to the ramus ophthalmicus profundus in the urodeles. Even 

 in the caecihans the terminal twigs of the medial maxillaris anas- 

 tomose with twigs of the profundus. 



In the Urodela the writer ('13) finds the ramus mandibularis 

 Y to have the following characteristic branches: 1) small short 

 motor branches to the temporal and posterior masseter muscles 

 as the main nerve passes through the muscles; 2) a large sensory 

 branch {md.2) supplying the skin in the region of the angle of 

 the jaw; 3) a motor branch {md.l) supplying the pterygoid and 

 anterior masseter muscles and sending an anterior division into 

 the antorbital muscles; 4) a sensory branch, or branches {md.3) 

 innervating the skin overlying the jaw in the region of the origin 

 of the main nerve; 5) the main mandibular nerve {md.Jj) supply- 

 ing the skin overlying the greater part of the lower jaw, w^ith an 

 alveolar branch {md.Ji.o) that unites with an alveolar branch of 

 the facialis; 6) a posterior branch {md.5) which supplies the 

 intermandibular muscles and the overlying skin. All these ex- 

 cept md.3 are distinctly differentiated in the caecilians. 



In the Urodela the ramus ophthalmicus profundus shows four 

 characteristic divisions: an ophthalmicus profundus minor (op.l), 

 given off near the ganglion and supplying the top of the head, 

 and three terminal divisions, medial, lateral, and ventral. The 

 medial division, nasalis internus (op. 2), supplies the snout region 

 dorsally; the lateral division, nasalis externus {op. 3), supplies 

 the side region of the snout, and the ventral (op. 4) forms the 

 anastomosis with the ramus palatinus VII. The latter division 

 is absent in caecilians, unless the branch designated as op.2v 

 represents it. An ophthalmicus profundus minor (op.l) is 

 doubtfully present in caecilians. Posteriorly it may be repre- 

 sented by the dorsal sensory branch (Vd.) arising from the Gas- 

 serian ganglion, and anteriorly by the anastomoses of the ramus 

 ophthalmicus profundus with the facialis ramus (os.). The 

 nerve in the caecilians designated by the writer as op.l only in 

 part corresponds to an ophthalmicus profundus minor, for its 

 lateral extension seems to represent in part a nasalis externus. 



