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 chimseroid 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 1st of June, similar forms are 

 encountered, ranging from 8 to 10 mm. and upwards. The youngest of these, 8 mm. 

 in length in spirit (PI. 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. 



