198 



Part III. — Fifteenth Annual Report 



increase in the silvery hue of the sides. Microscopically, somewhat 

 rounded granular areas at intervals indicate the development of scales. 

 When the fish is 45 mm. in length, the developing scales are more 

 evident, as minutely reticulated areas scattered throughout the skin, 

 and causing a slight opacity where each is situated (PI. VII. fig. 1). 

 The area of finely dotted pigment above the pectoral is more densely 

 covered. In contrast with the whiting of the same length, it is a much 

 stouter fish, the head and eyes are larger, the belly more capacious ; and 

 though, in both, the tips of the ventrals (long second rays) project 

 beyond the vent, yet the length and strength of the haddock's 

 fins are characteristic, and they also retain their pigment in spirit. 

 Parasitic Caligi, further, seem to be partial to this species. The long, 

 sharp, recurved teeth of the whiting are more prominent than those of the 

 haddock, the mouth of which is also more neatly formed. The vent of 

 the former is considerably in front of that of the latter, and the first anal 

 fin is in full development. There is little confusion with the young cod 

 of similar length since — before it reaches this size — its sides are beautifully 

 dappled, its mouth larger, the barbel much longer, the ventral fins fall 

 short of the vent, and the body of the fish is less compact, while the head 

 has a different outline. No black pigment occurs on the rays of the 

 pectoral or pelvic fins. The dusky hue of the green cod and the pollack 

 — both of which show the median line of black pigment along the centre 

 of the body posteriorly — readily separates them. Both lean to the cod 

 in regard to the proportions of the pectoral and pelvic fins. 



At 48 mm. the general silvery hue is even better developed, and, whereas 

 at the latter stage (39 mm.) the lateral line, though present, was but feebly 

 marked, it now forms a prominent papillose ridge from the upper opercular 

 region almost to the tail. The larger black chromatophores scattered 

 amongst the minute are more conspicuous on the sides of the haddock 

 than in the whiting, and, indeed, they give it a characteristic appearance. 

 The condition of the vent at this and the previous stages is also noteworthy, 

 for about eight isolated papillae occur round its edge, with the genital 

 papilla behind. It may be that slight sexual distinctions appear at these 

 stages which afterwards disappear. The boldness of the pigment and 

 the larger scales are characteristic features when compared with a young 

 whiting of the same size. The tip of the mandible is nearly in a line 

 with the premaxillary, and thus not evidently underhung. 



The little haddock grows rapidly, and at 53 mm., that is about 2-| 

 inches, the dark patch behind the shoulder — so characteristic of the 

 species — is readily seen by the unaided eye (PI. VII. fig. 4). The 

 cupreous lustre seems to bring out the pigment, since the condition is 

 just as in the smaller forms, viz., a finer distribution of minute black 

 pigment-specks. The'pectoral fins have a yellowish-brown hue, with black 

 chromatophores on both sides as before, and they stud the fin with minute 

 black streaks arranged longitudinally. The amount of black pigment in 

 the three dorsals is noteworthy. The ventrals are pale, but they still 

 have black specks arranged in a linear manner in the centre. They are 

 now proportionally shorter, a clear space existing between them and the 

 vent, — which is papillose. Both anal fins are streaked with black pigment 

 only in a less degree than the dorsals. The head and body are minutely 

 and uniformly dotted with black, while the brain is reddish. The 

 eyes are large and silvery, the latter likewise being the condition of 

 the sides. The scales, which are now much larger, cover the skin 

 much more closely, thus giving a regularly reticulate condition to the 

 surface (under the microscope). Where they project from a torn 

 surface, as in the sketch (Plate VII. fig. 2), * reticulation of the 



