140 



THE ANATOMY OF VEETEBRATED ANIMALS. 



hyoidean arch (Hy) and, indirectly, to the jaws. The latter 

 consist of a palato-quadrate cartilage (D) united by liga- 

 ment with its fellow, and with the prefrontal region of the 

 skull at F. ; and presenting, at its posterior end, a con- 

 vex articular head to the cartilage of the mandible, or 

 Meckelian cartilage, Mn. It is obvious that A, B corre- 

 sponds with the hyomandibular, or suspensorial, cartilage 

 in the Sharks and Rays ; D, with the palato-quadrate ca.rti- 



Fig. 39. 



Au /isf 



'I' asc 



Fig. 39.— Side-view of the skull of Spatvlaria, with the beak cut away, 

 and the anterior (asc), and posterior (psc), semicircular canals 

 exposed: — Au, auditory chamber ; Or, the orbit with the eye; N, 

 the nasal sac; J^, the nyoidean apparatus; Sr, the representatives 

 of the branchiostegal rays ; Op, operculum; Jfn, mandible; A, B, 

 suspensorium ; D, palato-quadrate cartilage; E, maxilla. 



lage, or so-called " tipper jaw," and the cartilage of the 

 mandible with the lower jaw in these animals. But, in 

 the Ganoid fish, an osseous operculum (Op) is attached to 

 the hyomandibular ; and a branchiostegal ray [Br) to the 

 more strictly hyoidean part of the skeleton of the second 

 visceral arch ; while a membrane bone (JB) i-epresenting the 

 maxilla, and another [Mn) the dentary, of the lower jaw in 

 Teleostei, are developed in connection with the palato-quad- 

 rate and mandibular cartilages. 



