818 PROFESSOR W. C. M‘INTOSH AND MR E. E. PRINCE ON 
A fortunate sweep of the trawl-like tow-net on the 1st June gave a complete series 
of fresh specimens, from the form just described to other stages formerly seen. The 
smallest cod were 5 mm. in length, but they were even younger than the somewhat 
stunted specimens reared in confinement. They had the two post-anal bars, the sub- 
notochordal black band, and the scattered spots on the head and jaws; and they were 
further characterised by the greenish-yellow colouration on the head and snout, as well as 
along the dorsal region of the body, a feature so marked at a somewhat later stage; the 
swim-bladder (which appeared to have a short or rounded form) was distinct. The tail 
and marginal fin did not differ from the stage mentioned on the previous page. Almost 
the same remarks apply to those 6 mm. in length, some of this size presenting a 
pinkish abdomen from the oil of the minute copepods they had swallowed. At 7 mm. 
the marginal fin has many embryonic rays ; moveover, the two post-anal pigment-spots 
have spread out, so that they form a dorsal and a ventral band, though two denser regions 
indicate their former condition ; a median line also occurs laterally. The yellowish-green 
tinge is better marked. 
In small forms 6 mm. long in spirit, and probably corresponding to the stage last 
mentioned (7 mm. when fresh), the marginal fin is quite continuous, commencing 
ventrally behind the well-formed anus and passing round the tail to a point on the 
dorsum a little in front of a vertical line from the vent, though in front of this a 
membranous margin projects a short distance, indicating probably a further extension of 
the fin. Fine embryonic rays are present throughout, except in the caudal region, where 
slight linear thickenings dorsally and ventrally indicate the commencement of the 
permanent rays. The pectorals are large, with a chimeeroid base and a fan-like membrane 
with embryonic rays. No trace of ventrals is visible. The mandible is bent upward 
when closed at a little more than a right angle to the body, and the angle of the jaw is 
very prominent. The eye shows a notch dorsally, and a well-marked choroidal fissure 
inferiorly. A little black pigment exists on the snout and the top of head, and along each 
side of the dorsal and ventral marginal fin, while a streak also occurs in the middle line 
laterally in front of the tail. The same pigment appears in touches on the prominent 
edges of the mandible, and along the ventral surface of the abdomen. 
In the beginning of May again, and also the Ist of June, similar forms are 
encountered, ranging from 8 to 10 mm. and upwards. The youngest of these, 8 mm. 
in length in spirit (Pl. XIX. fig. 2), still presents the embryonic fin from a point on the 
dorsum distinctly behind the vertical from the pectorals all round to the vent, the tail 
as yet showing no special differentiation. At points, however, corresponding to the two 
posterior dorsals and the two anal fins, thickenings—indications of the adult fins just 
mentioned—beyond the body-line are noticed, at the base of the embryonic fin. Beyond 
these rudiments the embryonic fin is unaltered. The tail forms a perfectly symmetrical 
organ, convex posteriorly, and having the notochord as a straight, tapering, and translucent 
streak in its centre, with the hypural and epiural elements disposed ventrally and dorsally, 
and so equally that the whole presents a lancet-like figure in the middle of the tail. 
