1:V) 



ZOOLOrxY 



SECT. 



the pharyngobranchials of the last two arches are fused together- 

 The next in order — the e^nbranchiah (cj). hr.) — with the exception 

 of those of the hist arch, bear a number of slender cartilaginous 

 rods — the hranchial vr^y-s —which support the walls of the gill-sacs; 

 and the next — the ceratohr and dais {ccr. hr.) — are, with the same 

 exception, similarly provided. The Jtypohrancldah (hyp. hr.), which 

 succeed these, are absent in the case of the first and fifth arches. 

 In the middle line on the floor of the pharyngeal cavity is a mesial 

 cartilage — th.QhasibranchiaJ (Fig. HI'i, h.hr.) — which is connected 



hi/p.br. 



ph.hr.a 



Fid. 814. — XXetniscyllium, ventral view of the visceral arches. Letters as in ])recediiig figure. 

 In addition— 6. In-, basiljranchial plate ; eer. lir. ceratobraiichials ; hyp. Or. hypobranchials. 



with the ventral ends of the third, fourth, and fifth arches. A 

 series of slender curved rods — the cxtrahranchiah — lie superficial 

 to the branchial arches, along the borders of the corresjjonding 

 external branchial clefts. 



Two pairs of delicate labial cartilages are present at the sides 

 of the mouth, and a couple at the margins of the openings of the 

 olfactory capsules. 



The skeleton of all the fins — paired and unpaired — presents a 



