DEVELOPMENT AND LIFE-HISTORIES OF TELEOSTEAN FISHES. 819 



A little pigment exists in the interspaces of the rays over a limited area dorsally and 

 ventrally. The pectorals have a large — almost semicircular — basal region, and a fan- 

 shaped series of rays distally, so that they are still powerful, but the ventrals are visible 

 only as two minute ventral papillae on the throat in front of the former. The body and 

 tail have increased considerably in bulk, but the head and anterior region still remain of 

 great proportional size. The angle of the mandible is prominent, and the jaw has the 

 larval slope upward and forward. The eye retains its great size. The black pigment 

 occurs on the top of the head — on which the chromatophores are now larger, along the 

 base of the dorsal, and less distinctly along the base of the ventral marginal fin, with a 

 streak in the middle line of the body towards the caudal region. The only other pigment 

 is in the abdominal region — from the top of the pectoral in a line downward and back- 

 ward to the anus, and this for the most part is internal. Yellowish-green pigment also 

 occurs here and there all over the surface, so that the animal when living presents a 

 greenish translucent aspect, and it is also noteworthy that the dorsal pigment is in two 

 sections on each side, thus indicating the two original spots. The eyes at this stage are 

 proportionally large, as in others of the group, of a bluish silvery aspect, and with 

 a dark arch of pigment superiorly. The bluish sheen is probably due to interference, 

 and not to any special pigment. The abdomen has a slightly pinkish hue from the 

 Crustacean food which filled both stomach and intestines. The branchiae show simple 

 papillae. 



At a somewhat older stage (PI. XIX. fig 3) the three dorsal fins are distinct, as also 

 are the two anal. It may be noted also that the first dorsal develops somewhat later than 

 even the two succeeding fins, that is to say, it presents only a thickening, while they 

 have rudimentary rays — for instance at a length of 10 mm. and 13 mm. In the latter 

 the swim-bladder assumes a more elongate aspect. The ventrals show more evident rays, 

 the growth of the body and head diminishes the proportional size of the eye. • The snout 

 is longer, so that the mandible bends less obliquely upward than in the previous stage. 

 The blackish pigment has increased on the lines formerly mentioned, and also at the base 

 of the abdomen. While in the earlier stages the tail of the young cod presents a straight 

 notochordal process posteriorly, it now (at and near three-eighths of an inch in length) 

 shows a distinct upward bend apparently from the development of the hypural elements 

 inferiorly. The tapering tip of the notochord issues therefore from the upper part of 

 the pointed central mass, the shape of the region, however, marking the usual 

 transformation caused by the shifting of the ventral margin to the posterior region of 

 the tail.* 



A month later, viz., on the 1st June, considerable progress had been made in the 

 growth of the young cod, which were caught both in the trawl and in the mid-water 

 net, sunk 3 or 4 fathoms in 6 or 7 fathoms of water, showing that these fishes gene- 

 rally seek the lower regions of the water. The length of the smallest was about ^f 



* The great length of the notochordal tip (embryonic tail) in Lepidosteus is noteworthy (Balfour and Parker, 

 op. cit., p. 374). 



