542 H. W. NORRIS AND SALLY P. HUGHES 



posteriorly along the lateral surface of the trachea, and a pos- 

 terior sensory ramus intestinalis which passes posteriorly at the 

 lateral border of the digestive tract (fig. 44, int.). 



The laryngeal muscles: In the late larval stage of Ichthyo- 

 phis, according to Goppert ('94), whose statements the writer 

 corroborates, there are five pairs of laryngeal muscles: 1) m. 

 hyopharyngeus (dorsolaryngeus a), (fig. 42, dla.), originating on 

 the fourth branchial arch in two parts, an anterior portion on the 

 ventral side of the arch and a posterior on the dorsal end of the 

 arch; the two parts of the muscle unite in an insertion on the 

 medial raphe ventral to the trachea, a few anterior fibers attached 

 to the ventral rectus series of muscles; 2) m. hyopharyngeus in- 

 temus (dorsolaryngeus b) (dlb) originating on the dorsal border 

 of the fourth branchial cartilage and posteriorly from connec- 

 tive tissue lateral to the pharynx, and meeting its fellow of the 

 opposite side on the middle line between the trachea and the 

 ventral wall of the pharynx, in part inserted on the lateral border 

 of the trachea; 3) m. dilatator laryngis (dorsolaryngeus c), (die), 

 originating on the fourth branchial arch close to the origin of 

 m. hyopharyngeus, and inserted on the lateral border of the 

 arytenoid cartilage; 4) m. sphincter (constrictor aditus laryngis) 

 (cal.) ; 5) m. laryngeus ventralis, inserted on the arytenoid car- 

 tilage and originating on the medial ventral line ventral to the 

 larjmx. 



In Dermophis the arrangement is fundamentally as in Ich- 

 thyophis, except that the laryngeus ventralis is not sharply dis- 

 tinct from the sphincter. The hyopharyngeal and sphincter 

 muscles are attached to the third (3rd -}- 4th) branchial cartilage. 



In Herpele the hyopharyngeus internus muscle is absent. The 

 following muscles attached to the larynx or in its immediate 

 neighborhood and innervated by the ramus laryngeus recurrens 

 X, occur (fig. 39) : 1) m. constrictor aditus laryngis (sphincter) 

 (cal.); 2) m. dorsolaryngeus (c) (dilatator aditus laryngis = dorso- 

 pharyngeus, Goppert) (die), inserted on the arytenoid cartilage; 

 3) m. dorsolaryngeus (a) (hyophar3mgeus, Goppert, in part ^ 

 dorsotrachealis, auct.) (dla.), inserted in a tendon connected with 

 the corresponding muscle of the opposite side beneath the 



