DEVELOPMENT AND LIFE-HISTORIES OF TELEOSTEAN FISHES. 821 



rock-pools of St Andrews in June and July, often hang in the water obliquely with their 

 heads downward against the current. Their food at this time, when they measure If 

 inch to If inch in length, consists of copepods, larval cirripedes, sessile-eyed crustaceans 

 (larval), small annelids, and Campontia, while the green cod, in addition to that food, 

 feeds upon minute Mollusca, e.g., Homalogyra rotata, and various species of Ostracoda. 

 The cod is less shy at this stage than the young green cod, and it is captured with less 

 difficulty. 



Viewed from the dorsum they have a general pale olive-green colour. The sides 

 are iridescent, with a pretty pinkish pearly lustre. The upper surface and sides of the 

 head to a level with the eyes are studded with dark pigment. A regular series of dark 

 pigment-spots runs along each side of the median dorsal line to the tip of the tail. 

 About eight dark blotches occur on looking at the median lateral line, and as these are 

 flanked by other dark patches in the upper lateral region, they give a very characteristic 

 appearance to the fish (PI. XVII. fig 8). This upper lateral region, just below the lateral 

 line, shows behind the operculum nine dark spots. The first three are continued on the 

 silvery belly, and then cease. The rest have connections with a series of median spots 

 (five in number) in the middle line — bands, in several instances, passing from two upper 

 spots to one lower median, or again bifurcating inferiorly. The ventral median line has 

 on each side a band of pigment, continuous with the bars just described; but the pig- 

 ment-corpuscles are less distinct than along the dorsal lines, except opposite the base of 

 the vertical fins, where the pigment is quite regular, and corresponds with the base of each 

 ray. The first two dorsals have the blackish pigment towards the tip best developed on 

 the membrane between the rays, the basal region being pale. The third dorsal has only 

 a little black pigment. A trace of pigment also occurs towards the commencement of the 

 anal fin. Blackish pigment is scattered on the sides and under surface of the mandible, 

 and a thin dark streak passes backward in the middle line. The eyes are of a pale 

 olive-green hue, with dark specks of pigment. The upper opercular region, and the 

 surface above the cerebellum, are of a pale pinkish colour, due to the blood-vessels 

 and the brain beneath. The vascularity of the latter seems to be considerable. The 

 opercular region and the body are silvery. The pointed teeth are very evident in the 

 jaws. 



The later stages have been dealt with in former papers, and need not be alluded 

 to at present, except in regard to Eimer's # notion that the markings in animals are 

 primitively longitudinal. Now the young cod is conspicuously speckled in its earliest 

 stage, and is rather pale and translucent in its next condition, the pigment which forms 

 the transverse bars gradually grouping themselves on a somewhat pale surface, without a 

 trace of longitudinal bands. In many other fishes, both round and flat (Pleuronectids), 

 the same arrangement obtains, so that Haake had good grounds for demurring to this 

 view from the study of the Australian fish Helotes scotus, which in the adult is marked 

 by eight longitudinal bands, while young specimens have in addition a row of clear 



* Zoolog. Anzeiger., viii., 1885, pp. 507-8. 



