34 



TIIK liOXKS AND JOIXTS. 



Fg. 21. 



14. The vomers, vainer (Figs. 19, 20 v). 



Cuvier, I.e., p. 389, PI. XXIV, Figs. I, 2 1 1. Duges, n. 6. Parker 

 9 and Bettany, I.e., vomer. 



A pair of flat bones, placed horizontally on the under surface of 

 the cartilaginous nasal capsule in the triangular space between the 

 palatine bone and the anterior portion of the arch of the jaw. They 

 limit the outer border of the floor of this capsule, which Jies in 

 a groove on the dorsal surface of the bone. The outer border of 

 each bone has three processes, and between them two notches ; the 

 hinder of these notches bounding the posterior nares. The inner 

 borders of the two bones touch, and the under surface of each bears 

 a transverse row of small, pointed teeth. 



15. The mandible, maxilla inferior (Fig. 21). 



Cuvier, I.e., p. 398, PI. XXIV, Figs, i, 2 rst. Duges. n. 16, 17, 18, 19. 

 Parker and Bettany, I.e., mandibular arch. 



The mandible consists of two bony arches united by ligament in 

 the middle line, and each formed of four pieces. These are, (i) the 



angulosplenial, a 

 strong-, bony piece 



which forms the in- 

 ferior and internal 

 part of the lower 

 jaw; below, it ex- 

 tends posteriorly, as 

 far as the articula- 

 tion ; in front, it is 

 attached to the clen- 

 tary. In the greater 

 part of its length it 

 has a groove directed 

 upwards and out- 

 wards (C, b}, and 

 above has a pro- 

 cess which repre- 

 sents the processus 

 eoronoideuft : (2) the 

 dentary (A 2, B 

 2), a bony lamella 

 which rests on the 



A Mandible of Rana esculenta, from above, nat. size. 



B External view of left side, ) f . t . 



. . , c i/wice uttv. iic. 



C Angulospleiiuil, 



1. Aagulosplenial. 



2. Dentary. 

 Mentcuneckelian. 

 Meckel's cartilage. 

 Rudimentary processus coronoideus. 

 Groove for Meckel's cartilage. 



3. 

 4, 4 



