296 THE COD FAMILY. 



barbels and the larger mouth. The first dorsal seems to be 

 nearly as long as in the species just mentioned. With the 

 appearance of the scales and the forsaking of a pelagic life, 

 a kind of metamorphosis ensues in the rocklings. 



An egg occurs in March at St Andrews which is probably 

 that of a rockling, other than the five-bearded species. It has 

 a diameter of '032 inch or '82 mm., being thus slightly larger 

 than Raffaele's measurement of the egg of the three-bearded 

 form. It has a distinct oil-globule and occasionally, in addition, 

 another definite pale area, slightly refractive and apparently 

 differentiated from the yolk, near the animal pole (Plate III, 

 fig. 9.) 



In manipulating the egg this oleaginous mass in some 

 specimens moved under the embryo and kept the egg floating 

 with the animal pole above, the reverse of the ordinary position. 

 The yolk is minutely streaked with short wavy touches and is 

 not perfectly transparent, but the streaks may be only superficial. 



The embryo developes slowly, black pigment appearing very 

 early, and forming a line of spots anteriorly on each side of the 

 body, and a few chromatophores below the oil-globule with the 

 addition rather later of minute round black spots on the surface 

 or margin of this body. The skin before hatching is vesicular. 

 On extrusion from the egg (Plate XI, fig. 8) the larva floats 

 with the ventral surface uppermost, and the oil-globule is 

 at the posterior and inferior part of the yolk (in this feature 

 closely resembling the figure given by Raffaele and referred to 

 above). About the fourth day after hatching the black pigment 

 becomes abundant, forming a broad lateral bar in front of the 

 tail-region and a small patch slightly more forward (cf. the 

 larval hake). By refracted light this pigment has a brownish 

 tint. Later (Plate XI, fig. 9) there appear two distinct black 

 pigment-bars behind the yolk-sac as in the five-bearded species, 

 but in this case the posterior is much the larger as well as the 

 first to make its appearance. On the head and sides of the body 

 the pigment has increased greatly. A peculiar feature was 

 noticed with regard to the circulation, in that the heart was 

 very late in commencing its pulsatory movements, a fact 

 possibly due to the severity of the weather at the time of 



