856 PROFESSOR W. C. M'INTOSH AND MR E. E. PRINCE ON 



fin-rays ; the position of the latter fin, moreover, is unaltered. Behind the anus the fine 

 rays of the anal fin are visible for some distance. A marked thickening, forming a rounded 

 boss anteriorly, now exists under the tip of the notochord, which is slightly bent up. 

 True caudal rays occur from the latter thickened region to the tip of the notochord, the 

 embryonic fin completing the margin dorsally and in front ventrally. The direction of 

 the inner border of this hypural thickening is from above downward and forward, the 

 pigment marking it externally. The tail is thus being pushed upward. This stage is 

 probably between two and three months old. 



The next stage (G) at present available is illustrated by a specimen procured on 

 1st July, and measuring 27-28 mm., or about 1^ inch. This has now assumed most 

 of the characters of the adult. Thus the head has become more elongated and com- 

 pressed laterally, and the upward bend of the mandible is marked. The depth of 

 the body has much increased, so that the fish appears to be shorter. The dorsal fin 

 is shorter, and has an elaborate muscular ridge at its base. It stretches from a line 

 over the tips of the ventrals to the first third of the anal. No part of it extends 

 in front of the ventrals — that is, it does not reach their anterior ends. A row of black 

 pigment-spots runs on each side of the dorsum backward to the dorsal edge of the 

 caudal. The anal begins at the posterior fourth of the body, instead of the posterior 

 sixth or seventh, as in the earlier stages, and such is therefore a distinctive feature. 

 The pelvic fins arise from a point rather in front of the middle of the body, and thus 

 their position differs from that in the adult. The pectorals are still proportionally 

 large, with a fan-shaped basal region and expanded rays. The caudal is deeply 

 bilobed. When viewed from the dorsum the head smoothly glides into the body — from 

 the great increase in the thickness of the latter. The caudal is homocercal, the basal 

 (or hypural) region having a double crescent, and the pigment has increased in this 

 and the neighbouring part of the base. 



This form may fairly be considered as representing at this period the direct continua- 

 tion of the stages formerly mentioned, though perhaps it is an advanced one of the series. 



The second series of the season commenced with two examples procured on the 30th 

 August. They nearly correspond with stage D of date 1 4th April. 



On the 24th September, again, three stages occur, viz., those corresponding to stage 

 E in spring; secondly, one, though only measuring 14 mm. in length, showing a further 

 stage of development than stage F of 16th May (and possibly a sprat), for the hypural 

 elements form a nearly straight vertical edge posteriorly, and the tip of the notochord 

 projects from the upper angle ; and thirdly, one a millimetre or two shorter than stage 

 F, but somewhat more advanced than the previous (stage 2) in regard to depth of body, 

 firmness of muscle, size of dorsal fin, and especially in the condition of the caudal, which 

 has a straight vertical edge, with the permanent dorsal rays developing over the tip of 

 the notochord. 



A considerable margin must thus be given in regard to the spawning period. 



On the 1st of October, again, one corresponding nearly to stage 2 of 24th September 



