240 THE COD FAMILY. 



attain as large a size as •25 inch, showing the retarding effect 

 that artificial rearing has upon the growth of these young forms. 



At Plate IX, fig. 3, is seen a post-larval form which is 

 probably a cod, about 206 in. long and showing many of the 

 above features ; the stomach is brightly coloured (pinkish) with 

 the oil of minute copepods which form the staple article of food 

 of these little fishes. The eye has a purple sheen, and the 

 choroid fissure is still prominent. Only two bars of pigment 

 remain, and the chromatophores on the head and jaw have not 

 yet made their appearance. 



A stage later is seen at Plate IX, fig. 4. This little cod 

 was about "226 in. in length and shows well-marked pigment 

 upon the head. The fusion of the two post-anal bands is 

 clearly shown, and there are also traces of a row of lateral 

 chromatophores in the caudal region. On the ventral surface 

 black pigment-specks are dotted from the jaw to the vent — 

 chiefly in the median line. The median fin is still continuous 

 from behind the vent to a point dorsally above it, though 

 carried by a slight membranous fold almost to the region of the 

 head. The latter is very large, the mandible prominent, and the 

 eye shows the choroidal fissure. This form might probably 

 be about 3 weeks old. It has already assumed the uniform 

 greenish yellow hue which is so marked a feature in more 

 advanced stages. 



In Plate IX, fig. 5, we have a stage '33 inch in length. The 

 median fin is continuous, though there are indications of the 

 adult fins. The tail is still quite symmetrical. The ventral 

 fins appear as a pair of buds below the pectorals, the head 

 and eyes are propoitionally large, and the mandible has the 

 same vertical tendency, emphasised when the mouth is closed 

 — as in the figure. The pigmentation is far more pronounced, 

 and includes a number of yellow chromatophores scattered over 

 the head and back (Plate IX, fig. 6). Soon after this stage 

 the little fish makes rapid strides in its development and 

 begins to assume the adult outline. The dorsal and anal fins 

 split off from the continuous embryonic fin and permanent 

 fin-rays appear. The tail assumes the adult form by gi-eater 

 development of the ventral (hypural) rays, thus bending the 



