348 



MANUAL OF ELEMENTARY ZOOLOGY 



Each branchial arch contains above a flat, pointed pharyngobranchial 

 which, starting beside the backbone, slopes forwards to join an epi- 

 branchial that lies at the side of the pharynx in a line with the 

 hyomandibular cartilage. From the lower end of this the cerato- 

 branchial runs forwards and inwards parallel with the ceratohyal and 

 mandibular cartilages. The first four ceratobranchials are connected 

 with kypobranchials in the floor of the pharynx. The first hypo- 

 branchial is small and joins the first ceratobranchial with the basihyal ; 



Fig. 249.- 



■The skeleton of the pectoral fins and girdle of a dogfish, 

 seen from the ventral side. 



cor., Coracoid region;^/., glenoid surface; h.r. % horny rays ; nipt., metapterygium ; 

 mspt., mesopterygium ; ptt., propterygium ; rod., cartilaginous rays; sc, 

 scapula. 



the three hinder are larger and directed backwards and inwards. The 

 last two pairs of hypobranchials and the fifth ceratobranchials join a 

 median basibranchial plate. The epibranchial, ceratobranchial, hyo- 

 mandibular, and ceratohyal cartilages bear gill rays along their hinder 

 borders. Outside the upper and lower jaws lie a pair of labial 

 cartilages, and along the outer sides of the second, third, and fourth 

 ceratobranchials are extrabranchiah. 



The median fins are supported by a skeleton consisting of several 

 series of rays. The series nearest the body are cartilaginous rods known 



