34 A. E. HEFFORD. 



am not able to state, because I had kept them together in the same 

 vessel, regarding them as of the same species ; but the very similarity 

 of eggs makes this point a matter of indifference. The larva (a), 

 which is 2'65 mm. long and pigmented to the caudal extremity, I 

 regard as Gadus minutus. Larva (b), on the other hand, which is 

 slightly larger (ca. 2*9 mm.) and shows heavier pigmentation, stopping 

 short so as to leave the caudal extremity bare, I consider is very prob- 

 ably G. lusms (cf. 10, Taf. X, Tigs. 20 and 21). Larva (d) (length 

 3 mm. with yolk absorbed) resembles (b), the posterior 0'5 mm. of the 

 caudal extremity being unpigmented. The small size for this stage of 

 development does not rule out the probability of its being G. luscus. 

 Larva (c) shows black pigment of less intensity, most of it occurring 

 along the ventral post-anal contour as far as the caudal extremity and 

 above the gut. There are only four dorsal post-anal chromatophores, 

 and these are not nearly so strongly marked as the ventral ones. This 

 I regard as G. minutus, especially on account of there being a distinct 

 resemblance to the early post-larval forms of this species, which have 

 been carefully descriljed by Schmidt (21a and b), and which are 

 common in my own collections. In the same way the bare-tailed 

 larvae (b) and (d) suggest the now well-known larval pout.* As to 

 the occurrence of yellow pigment, all four specimens showed yellow 

 chromatophores, with more or less distinctness on body, unpaired fins, 

 and yolk-sac, but in the post - vitelligerous specimen (d) this colour 

 had almost vanished except from the head (cf. Mcintosh, 14c, p 240). 

 Three planktonic eggs of 0*95 mm. diameter, which were taken in 

 the AYest Channel (entrance to Plymouth Sound) on 11th February, 

 may be either G. minutus or G. luscus. One-day-old larvae measured 

 2'95 and 2"8 mm. The black pigment consists of relatively large 

 stellate chromatophores on the head, a dorsal series which become 

 smaller and less closely placed towards the posterior extremity, and 

 a much weaker ventral series consisting of about nine post-anal 

 chromatophores and a faint line dorsal to the gut. There are small 

 specks of yellow pigment on the body and embryonic fins, most strongly 

 marked along the body contours and along the proximal margins of 

 the fins, but very faint in the caudal region. The larval pigment at 

 this stage cannot be said to show any approach to either the bib or 



* While using this similarity of larval pigment to that of definitely known post-larval 

 stages as evidence assisting to indicate the identity of a larva hatched from a Gadus egg 

 taken in the tow-net, I think it necessary to point out that this similarity should not 

 always be expected in the larval stages. As positive evidence it is helpful, but as negative 

 evidence it is without value. Under certain conditions — chiefly of higher than normal 

 temperature — I have noticed a jirecocity in development of pigment. The same phenome- 

 non has been noted by Holt (cf. 11a, p. 454). 



