Herrick, Cranial Nerves of Ambly stoma. 201 



for a short distance, when one turns abruptly dorsad the other 

 ventrad. 



The latter, the ramus mandibulatis (man.), will first be de- 

 scribed. It passes first through the m. pterygo-temporalis to 

 which it sends a small branch, then between this muscle and 

 the masseter to which it also sends a branch (mas.) Just before 

 entering the lower jaw it sends forward a small branch to the 

 skin of the angle of the mouth (a). Within the lower jaw it 

 divides into two rami, one above, the other beneath Meckel's 

 cartilage. The latter passes down through a short foramen be- 

 tween the dentary bone and Meckel's cartilage and then forward 

 along with the accessory hyo-mandibularis, with which it anas- 

 tomoses (c. hm.) It divides into two parts which subsequently 

 anastomose and supply the skin of the lower jaw and lip. This 

 ramus is apparently the mentalis of von Plessen and Rabinovicz, 

 though the dorsal ramus is probably the true ramus mentalis 

 (men.) This nerve follows the dorso-lateral border of the jaw 

 and finally enters a canal between the dentary bone and Meck- 

 el's cartilage. While within this canal it gives off branches to 

 the teeth and gums and divides, the smaller branch remaining 

 in the canal, anastomosing with the ramus alveolaris of the fa- 

 cial (c. m.) and then continuing forward to the teeth and mucous 

 lining of the lip. The larger portion of the r. mentalis then 

 leaves the dental canal and passes forward to the skin of the 

 lower lip. 



The ramus fronto-maxillaris lies between the m. masseter 

 and the m. pterygo-temporalis. It divides at once into the r, 

 frontalis (f.) and the r. maxillatis (max.) The former takes the 

 more medial and dorsal course, lying at first between the m. 

 temporalis and the skin on the dorso-lateral aspect of the head. 

 Farther forward it lies between this muscle and bulb of the eye 

 and contributes fibres to the skin of this region and the corres- 

 ponding parts as far forward as the tip of the snout. Just be- 

 hind the nostril it is joined by a branch of the r. ophthalmi- 

 cus (c. f.). 



The ramus maxillatis separates from the r. frontalis behind 

 the bulb of the eye and descends to the ventro-lateral border of 



