VISCEEAL SKELETON 213 



a. The pharyngo-branchials, the most dorsal elements, 

 are flattened rods running forwards and outwards 

 in the roof of the pharynx. The anterior ones are 

 connected with their fellows of the opposite side 

 by ligament ; and the last two of each side are 

 much smaller than the others, and fused together. 



"b. The epi-branchials are short broad plates attached 

 to the outer ends of the pharyngo-branchials. 

 With the exception of the hindmost they bear 

 gill-rays along their posterior borders. 



«. The cerato-branchials are stout rods running forwards 

 and inwards in the ventral wall of the pharynx, 

 and bearing gill-rays along their posterior borders. 

 The fifth or hindmost cerato-branchial is shorter 

 but much broader than the others ; it has no gill- 

 rays ; and its posterior border is deeply notched 

 to lodge the Cuvierian sinus (p. 227). 



■d. The hypo-branchials are small rods in connection 

 with the inner ends of the first, second, third, and 

 fourth cerato-branchials. The first hypo-branchial, 

 which is very small, is directed forwards, and 

 connects the first cerato-branchial with the basi- 

 hyal. The three hinder hypo-branchials are 

 larger, and are directed backwards. 



e. The basi-brancMal is an elongated flattened median 



plate, pointed behind. It is connected with the 

 two hinder pairs of hypo-branchials in front, and 

 at the sides with the fifth cerato-branchials. With 

 these latter, it strengthens and supports the dorsal 

 waU of the pericardial cavity. (Fig. 49, p. 224.) 



f. The extra-branchials are three pairs of elongated 



curved rods lying along the outer sides of, and 

 beneath the second, third, and fourth branchial 

 arches. 



The labial cartilages are two pairs of slender cartila- 

 ginous rods in the folds of skin at the sides of the 

 jnouth. 



