THE COD FAMILY. 247 



coast of Ireland). On the other hand, his larvae appeared to 

 have less pigment on the dorsal wall of the abdominal cavity. 

 In June they hatch in the short period of six days, and after a 

 week they take to the bottom of the vessel in still water, moving 

 actively when disturbed. At rest they hang with the front end 

 inclined downwards, as is also the habit in other very young 

 fishes under these conditions, and are difficult to see. The 

 prominent diagnostic features are the very large and pigmented 

 eyes, the black pigment-spots on the head and neck, on the 

 dorsal wall of the abdominal cavity, and along the ventral 

 muscle-plates behind the vent. There is no pigment on the 

 dorsal region posteriorly, and the yolk-sac and marginal fins are 

 also free from black chromatophores. As in the cod, the vent 

 is placed immediately behind the yolk-sac, and does not reach 

 to the edge of the marginal fin. 



When five days old the skeletal elements of the mandible 

 have considerably elongated, and the abdominal pigment has 

 increased. The oral chamber has burst through. The mouth 

 gapes, but only erratic movements of the parts take place. The 

 otocyst presents a ridge growing up from the floor, and a 

 chamber descending from the roof, the otoliths lying on each 

 side of the former. A lenticular mark indicates the anterior 

 nares. On the seventh day blood enters the heart, and the 

 circulation becomes active. The black pigment over the brain 

 and the medullary region, and the roof of the abdomen, is still 

 characteristic ^ The appearance of the young haddock on 

 the eleventh day is seen in Plate IX, fig. 10. 



The later post-larval stages of the haddock up till now have 

 not been recognised as such beyond dispute, and they have 

 probably been often confounded with those of the cod. It can 

 hardly be supposed that the post-larval stages of so common a 

 form can have defied all means of capture, and the similarity of 

 these two fishes would lead us to suppose that in the stages in 

 which the larval cod have lost their early transverse bars the 

 resemblance would be closer. Sars held that the post-larval 

 haddock could be recognised by their shorter and stouter form 



^ Mcintosh and Prince, Researches, p. 823, 



