of the Fishery Board for Scotland. 
333 
foregoing, the ovaries, however, having a similar structure. The capsule 
(zona radiata) encloses a minutely granular yolk, no special oil-globules 
being yet visible. In all probability the latter subsequently become dis- 
tinct, as in the former species, and then coalesce into a single large 
globule, which is so conspicuous in the larval sand-eel. In this species 
the oil-globule in the larva, so far as the diagnosis at present goes, is 
comparatively pale. 
In the Trawling Keport (1884) some attention was paid to the young 
sand-eels, and a more detailed account of the various stages from 6 to 7 mm. 
in length to the form of the adult, was given in the Researches by the 
author and Professor Prince. The majority of the earlier stages, however, 
had been described from spirit-preparations, or from dead specimens in 
the net. Further observations during the past year have tended to clear 
up some obscure points in the life-history of this species, and show the 
connection between it and certain larval and post-larval forms whose 
identity could not hitherto be established. 
In the paper referred to, after describing the various stages of the sand- 
eel, two unknown larval forms, I) and G, are mentioned. These are 
captured in large numbers every year about the beginning of March, and 
since, during several seasons, the nets have been frequently at vrork before 
their appearance, it is clear that if such had sprung from a pelagic egg it 
would have been captured in greater or less numbers. Further, these larval 
forms appear somewhat abruptly in great numbers, the bottom nets captur- 
ing them in hundreds ; and as they measure about 5 or 6 mm., and have 
very little yolk as a rule, they would seem to spring from demersal eggs. 
In size they are somewhat less than the herring when newly hatched, while 
the position of the vent and the occurrence of a large oil-globule, often sur- 
rounded by a protoplasmic investment, in the yolk are diagnostic (Plate 
XIIL fig. 9). In no instance has one with a large yolk been captured, 
so that either this is small at first and rapidly absorbed, or the larvse 
have been carried some distance by currents. The duration of the 
embryonic development of the sand-eel is yet unknown, but it would 
appear that the majority of the specimens of A. tohianus examined 
could not be ready to spawn for a considerable period after the end of 
May. How then is the gap to be filled up between this period and the 
appearance of the multitudes of young in March ? The frequent use of 
the bottom trawl-like tow-net fixes the date of the first appearance of the 
larvae with tolerable certainty, and further shows that they by-and-by 
diminish in number, only a very few being procured towards the end of 
May. The difficulty would be obviated if it were found that these sand- 
eels did not spawn, or that their spawning period was prolonged till late 
in the year, e.g., in December or January, and that the egg developed 
slowly after deposition. The yolk is faintly granular, and in some the oil- 
globule diminishes to a speck before it disappears. In others the yolk is 
absorbed and the oil-globule left. This appears to be the case in the form 
termed Gf, which in other respects agrees with DJ. As these larvae get 
older the vent reaches the border, and the double line of pigment, i.e., one 
on each side, distinguishes them from the gunnel, which has certain 
resemblances to the sand-eel at this stage (after absorption of the yolk). 
As formerly mentioned, a single line of pigment stretches from the 
pectorals a short distance backward in the middle line, and then a double 
series of very distinct black chromatophores pass on each side of the gut to 
the anus. Behind the latter a single median line of black chromatophores 
\ * Trans. Boy. Soc. Min., pp. 860, 861. 
t Op. cit., pi. viii. fig. 1. 
X ' Pelagic Fauna,' &c., 1889, pi. iii. fig. 8, and pi. iv. figs. 2, 3, 4. 
