150 



ZOOLOGY 



the pharyngobranchials of the last two arches are fused together- 

 The next in order the epibranchicds (ep. br.) with the exception 

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

 rods the branchial rays which support the walls of the gill-sacs ; 

 and the next the ceratobranchials (ccr. br.) are, with the same 

 exception, similarly provided. The hypobranchicds (hyp. br.), 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 the basibranchial (Fig. 814, b. br.) which is connected 



mck. 



hyp.br. f 



ph.br. J 



FIG. 814. Hemiscy Ilium, ventral view of the visceral arches. Letters as in preceding figure. 

 In addition b. br. basibranchial plate ; cer. br. ceratobrancliials ; hyp. br. hypobranchials. 



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

 series of slender curved rods the cxtrabranchials lie superficial 

 to the branchial arches, along the borders of the corresponding 

 external branchial clefts. 



Two pairs of delicate labial cartilages are present at the sides 

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

 olfactory capsules. 



The skeleton of all the fins paired and unpaired presents a 



