330 ICHTHTOLOGICAL CONTRIBUTIONS. 



remains containing tlie oil-globule^ whicli is still conspicuous. The 

 moutli is developed and open^ and indications of the gill arches are 

 seen behind the head. The intestine has increased so much in 

 length that it makes a single coil in the neighbourhood of the 

 stomach. The pectoral fin is rather large. The choroid of the eye 

 is deeply pigmented. With regard to the pigmentation of the skin, 

 only the position of the chromatophores is represented in the figure. 

 The black were arranged in a series along the dorsal and ventral 

 edges of the body, and in a group about the oil-globule. There 

 was no pigment at all in the larval median fin-fold. The iris of the 

 eye appeared bright blue, and there was a large irregular patch 

 of light yellow close behind the eye on the side of the head. In 

 my figure of the newly hatched larva I represented the pigment as 

 black and green, the green colour being present not only behind 

 the eye, but round the oil-globule and at three other points. The 

 explanation of the difference is that the green colour is due to the 

 mixture of black and yellow pigments, as in the adult mackerel. In 

 the larva at present described the yellow pigment is not mixed with 

 the black, and its appearance is therefore not altered. I do not 

 suppose that the distribution of pigment in the larva now described 

 is absolutely constant in all larv£e at this stage — on the contrary, I 

 believe it is subject to considerable individual variation ; but the 

 absence of chromatophores from the median fin-fold appears to be 

 constant and characteristic of the mackerel. 



DESCRIPTION OF PLATE XIV. 



Fig. 1. — Larva of Scomber scomber, the mackerel, drawn Jmie 15tli, 1891, liatched 

 June 11th. Zeiss A3, oc. 3, camera. Actual length 4-3 mm. 



f'lG. 2.— Larva of Solea vulgaris (or *S'. lascaris), caught August 9th, 1892. Drawn 

 from life with camera lucida. Actual length 11 mm. a, b. Air-bladder. 



4. Growth of Young Hekking in the Thames Estuary. 



I AM indebted to Mr. E. W. H. Holdsworth, author of the well- 

 known work on Deep Sea Fishing and Fishing Boats, for some 

 references to passages bearing on this subject which had not come 

 under my notice when I wrote my paper on the Rate of Growth of 

 Sea Fishes for the previous number of this Journal. In that paper 

 (see last number, pp. 240, 241) I stated that I had been unable to 

 find any record of observations on the spawning of herring at the 

 mouth of the Thames in spring. Mr. Holdsworth has directed my 



