374 ZOOLOGY, 



with the cranium by two points (on the vomer and temples). 

 Inferiorly it gives attachment to the lower jaw, posteriorly 

 it is prolonged so as to form a moveable covering, called the 

 gill cover. Three bones on each side form the lower jaw, 

 which articulates by a concave surface with the jugal ap- 

 paratus, just described; finally, an assemblage of bones is 

 found at the bottom of the mouth supporting the gills, 

 and seemingly analogous to the hyoid apparatus (Fig. 384), 

 extremely developed. 



t p io 

 Fig. 383. Bones of the Head of the Pike.* 



The bone of the tongue (I) is continued backward with a 

 series of pieces, and articulates on each side with a very long 

 and very large lateral branch (), and this by its opposite 

 extremity is suspended to the lateral partition of the head, 

 already described. These lateral branches, formed of several 

 bones, support inferiorly a series of flattened curved rays (r), 

 which assist with the circular to complete the walls of the 

 branchial cavities ; these are the radii branchiostegi. Behind 

 these branches there descend from the median portion of the 

 hyoid apparatus four pairs of osseous arches (a), which ulti- 

 mately are attached to the basis of the cranium by means of 

 some small bones, called superior pharyngeal bones (ph) ; 

 these arches carry the gills, and for this reason are called 

 branchial arches. Still further back, at the entrance of the 

 gullet, are the two inferior pharyngeal bones, so disposed as 

 to be applied against the superior. 



* c, cranium or orbit ; n, nasal fossae ; im, intermaxillary bone ; m, supe- 

 rior maxillary bone ; t, a kind of lateral partition separating the cheek from 

 the mouth, and which articulates forward with the vomer by means of the 

 palatine arches, above with the cranium (c), below with the lower jaw, behind 

 with the pre-operculum (p), which, in its turn, supports the operculum (op) ; 

 io, the pre-operculum bone, followed by the sub-operculum. 



