102 ZOOTOMY. 



In the Haddock the lateral line (see 82), is black, and there is also 

 a blackish blotch below the lateral line, between the pectoral and the 

 first dorsal fins : in the Whiting there is a black spot on the axil of 

 the pectoral fin. 



8 1. Remove a few scales and examine under a low 

 magnifying power ; each is seen to be a flat, rounded plate, 

 composed of concentric laminae of calcific matter, devoid 

 of bone-cells ; its anterior end is embedded in the derm 

 and overlapped by other scales, its posterior end is covered 

 only by epiderm, and presents an even free border ("cycloid '' 

 scales). 



82. The lateral line, a horizontal row of peculiarly 

 modified scales, lodging sensory tubes ; it passes from the 

 tail forwards, a little above the middle line of the body, and 

 becomes indistinct on the head 



83. The large mouth, at the extreme anterior end of 

 the body, supported below by the mandible (Fig. 29, d) and 

 above by the premaxillae (p.mx] and maxillae (mx), of 

 which the latter are behind the former and do not actually 

 enter into the gape. The skin in which the maxilla and pre- 

 maxilla are contained is so loose as to render the upper jaw 

 slightly protrusible. 



84. The teeth are best seen at a later stage ( 159 

 163, p. 120). 



85. The barbule (Fig. 30, ), a median filamentous 

 process, hanging from the under side of the lower jaw near 

 the symphysis. 



In the Cod the barbule is as long as or longer than the eye : in the 

 Haddock it is very short : in the Whiting absent. 



86. The nostrils (anterior nares) (Fig. 30, ;/.<*), situated 

 a short distance behind the blunt anterior extremity of the 

 snout; these are two small apertures on each side, of which 



