GADUS. 331 
and the consequent modification in development is in an intermediate 
position. The three types will be compared after the frog has been 
dealt with (see page 358). 
III.—GADUS. 
PHYLUM - CHORDATA (p. 402). 
SuB-PHYLUM VERTEBRATA (p. 405). 
Cass PISCEs (p. 434). 
ORDER TELEOSTOMI (p. 437). 
The haddock (Gadus eglefinus) is one of the commonest and best 
known of our British fishes. It is described here as a type of the order 
Teleostomé or bony fishes. The haddock is a smaller fish than the cod 
but larger than the whiting; all three belong to the 
oe ane large family of Gadide. It frequents the deeper offshore 
Habits, : 
water and is a ground-feeder upon small Crustacea, 
Mollusca and Annelida. The freshly-caught haddock is of a beautiful 
colour. The ventral surface is « pearly-white which gradates up 
Fig. 235.—LATERAL View oF THE Happock (Gadus aglefinus) x %. 
(Ad nat.) 
Lateral Line. 
i and Dorsal Fin. 
J ae 3rd Dorsal Fin. Caudal Fin, 
eZ u 
ist Dorsal Fin. Zp 
“end Anal Fin. 
Yes 
Operculum. // Won. 
\ \ 
Pectoral Fin. Pelvic Anus. | Aper. ist Anal Fin. 
Fin. Genital Aperture. 
each side into a metallic violet darkest along the dorsal surface. 
Along each side is a thin black line, the /ateral dine, extending from 
the head backwards to the tail. Just below the anterior part of this 
line there is on each side a black spot of pigment. The eyes are 
silvery and black. The whole body is enclothed in an 
ae investing coat of delicate overlapping cycloid scales, 
* developed in the dermis and carrying no spines. The 
skin is extremely slimy, as in the skate. : 
At the anterior end of the head is a large gaping mouth armed with 
upper and lower rows of teeth. Below the chin is a small sensitive 
