of the Fishery Board for Scotland. ,47 



i 



Some of the larvae had hatched out by 17th July. One is shown in fig. 

 2, PL II. After preservation in formaline it measured 5-5 mm. in total 

 length. The head-end of the larva is very black. The oil globule has a 

 large amount of black pigment associated with it. The pectoral and pelvic 

 fins are short and rounded. The first head filament is seen as a thick 

 papilla rising from the hind region of the head. 



In a specimen examined five days later (fig. 10), two of the head filaments 

 are visible. The young form, after preservation in formaline, was 6 mm. 

 long. The anterior filament is already long ; the posterior one is very short. 

 The pelvic fin is now much elongated, and is a narrow process. 



Another which was taken from the tank on 24th July, ».e., seven days 

 after the larvfe were first noticed, possessed three head filaments (fig. 9). 

 In formaline it measured 8 mm. in length. The pelvic fin had increased in 

 size ; a small angle at the base of the fin indicates the rudiment of the 

 second branch. The yolk was much reduced in quantity, but there was 

 still some present. The eyes of the little fish when alive were blue. 



On 29th September, i.e., about ten weeks after the arrival of the eggs, 

 the sole remaining larva was examined (fig. 6). It measured, when pre- 

 served, 9 mm. in length. The three head filaments Avere rather longer than 

 in the stage just described. The pelvic fin had further increased in length ; 

 it was now about half the length of the fish. It had, moreover, a short 

 second branch. 



I obtained a young Lophim piscatorius in Loch Fyne, near Otter, in a 

 tow-net worked horizontally about 5 fms. below the surface on 28th 

 July, 1899. It is shown enlarged in fig. 17. It seemed to be still in the 

 larval condition, although I was not able to make out whether there was 

 still yolk present or not. It was examined after preservation in alcohol. 

 It was quite black, except for its colourless marginal fin, and the colourless 

 sub-epidermal spaces on the head. The tail was twisted, and that prevented 

 an exact measurement of its length. It was then about 7 mm. in length. 

 The operculum ioperc.) was comparatively large. The pelvic fin was a 

 single branch, with a broadened base. Only two head filaments were 

 present. A parasite {p.) was adhering to the anal marginal fin. 



The sketches here given illustrate stages which diff'er slightly from those 

 described by Prince. The drawings of Agassiz have been reproduced 

 in " Scandinavian Fishes," and also by Gill.* They also differ in details 

 from the present material. In the latter the second branch of the pelvic 

 fin was only visible in the last described stage, whereas it was a long 

 branch in one of Agassiz's figures, which, judged by the size of the head 

 filaments, would be near that of my fig. 9. Prince's larva of the fifteenth 

 day approximates the condition shown in fig. 6. He describes the histo- 

 logical structure of the embryo and of the larvae of one, nine, and fifteen 

 days. A post-larval form, 7 mm. in length, was described by M'Intosh and 

 Prince. t The changes between the advanced larva described by Prince and 

 this post-larva are inconsiderable. 



The head filamehts are much further back in the larva than they are in 

 the adult. In the latter the first filament occupies a position close to the 

 upper lip. The head filaments are supplied from the last cranial nerve {vagus). 

 The branches to the filaments run forward over the top of the skull 



A sample of the spawn of this fish was obtained on June 25th, 1908, five 

 miles east of Loch Bracadale, Skye, by Mr. Alex. Mitchell, Lossiemouth. 

 Mr Mitchell, who had attended the class for fishermen at the Laboratory, 

 preserved a portion of the spawn and forwarded it to me. It seems probable 

 that the spawn of this form may not always reach the surface. 



* "The Life-history of the Angler." Smithsonian Miscellaneous Collections, No. 

 1569. Washington, 1905. 



t " Development and Life-histories of Teleostean Food tiud other Fishes." 

 Trans. Roy. Socy. Edinburgh, Vol. xxxv., Pt. iii., 1890. 



