184 EDWARD PHELPS ALLIIS, JUN. 



transverse level of the anterior end of tlie palato-quadrate 

 cartilage, where they become small and are lost. The two 

 Dackwardly directed branches run downward to the dorso- 

 lateral corner of the pharynx. One of them there continues 

 backward, giving branches to the adjacent tissues. The 

 other, larger branch runs downward vintil it reaches the 

 superior surface of the mandibular cartilage, that surface 

 being here directed dorsally and mesially. There it turns 

 forward and continues in that direction, lying immediately 

 ventro-mesial to the lower edge of the band of mandibular 

 teeth. In that position it gradually diminishes, and finally 

 disappears, being traceable with certainty, only to, approxi- 

 mately, the transverse level of the angle of the mouth. It 

 lies, in this distal part of its course, in the deeper part of a 

 fold of the tissues of the mouth cavity, and its relations to 

 this fold, as well as its general course and position, show, 

 beyond question, that it is the houiologue of the nerve identi- 

 fied by Grreen (27) as the chorda tympani in the several 

 selachians examined by him. This identification of the chorda, 

 by Grreen, is said by him to be based on the homologies pro- 

 posed for that nerve by Herrick, in his Menidia paper, and is 

 further discussed below. 



In Eaia and Spinax, Stannius (59) says that the nervus 

 palatinus is represented by three branches, a delicate posterior 

 one, and two stouter anterior ones. One of the anterior 

 branches is said by Stannius to be the true ramus palatinus. 

 The other is considered by Herrick (32) and Green (27) as the 

 homologue of the chorda tympani. The posterior branch is 

 said by Stannius to arise from the ramus palatinus by two 

 roots, these roots later uniting to form a single nerve, which 

 later receives an anastomosing branch from the nerve above 

 identified as the chorda tympani. The three branches that I 

 find, in Mustelus, arising from the orbital part of the nervus 

 palatinus thus together represent the posterior branch of 

 Stannius' descriptions plus the communicating branch from the 

 so-called chorda tympani, this latter nerve in Mustelus being 

 wholly separate and independent of the other three. The 



