554 PISCES—FISHES. 
The first or mandibular arch is believed by many to form Meckel’s ° 
cartilage beneath, and the palato-pterygo-quadrate cartilage above. 
Meckel’s cartilage becomes the foundation of the lower jaw, and bears 
a large tooth-bearing membrane bone—the dentary, a small corner 
bone—the angular, while the articular element is a cartilage bone. 
Of the bones associated with the upper part, the palatine lies in front, 
the quadrate articulates with the lower jaw; while between palatine 
and quadrate lie the pterygoid, the mesopterygoid, and the meta- 
pterygoid. 
The second or hyoid arch is believed by many to form the hyo- 
Fic. 296.—Pectoral girdle and fin of cod. 
fr., Fin-rays ; 8.0., brachial ossicles; cor., coracoid; se., scapula; 
ed., clavicle; .cZ., post-clavicle ; s.cZ., supra-clavicle ; 4.2., post- 
temporal. 
mandibular and the symplectic above, and various hyoid bones beneath. 
The hyomandibular, and its inferior segment the symplectic, connect 
the quadrate with the side of the skull. Of the six hyal bones, the 
largest and most important is the ceratohyal, which bears seven long 
branchiostegal rays. It is important to note that the bones formed 
in connection with these arches do not yet form an integral part of the 
skull. 
The toothed premaxilla forms the upper part of the gape, while the 
maxilla which articulates dorsally with the vomer, and nearly reaches 
the quadrate posteriorly, does not enter into the gape. Both are mem- 
brane bones. 
