and Growth-rate of the Lesser Sand-Eel. 287 
food to other fishes, both in its early post-larval stage, when 
it covers the sandy shallows with innumerable hosts, and 
later, in the surface-water, before assuming the adult habit, 
As regards the actual rate of growth of the sand-eel, it is 
obvious that a line equidistant from the two limiting lines in 
Table II. will furnish the mean growth-curve. 
Summarizing, we may say that a sand-eel spawned in 
December or January, after a (conjectural) quiescent larval 
period imbedded in the sand, emerges upon the surface of the 
latter at a length of about 4 to 5 millim. At this stage the 
supply of yolk-material is usually exhausted, and the oil- 
globule only remains. 
The post-larval sand-eel remains at the bottom till a length 
of about 10 millim. is reached. Living alongside of it are 
found great numbers of larval and post-larval herrings, 
usually somewhat larger, and young Sagitte. There is a 
‘remarkable superficial resemblance, caused solely by the 
attenuated form of these three very diverse organisms, which 
is, of course, entirely absent in the adult stages. 
At a length of somewhat over 10 millim. the young sand- 
eel commences its migration upwards through the mid-water, 
and at this period its growth is very rapid. ‘The average date 
for this change of habit will be seen to be about the end of 
April (see ‘lable II.), sometimes earlier *. By about the 
third week in May, or sometimes earlier, the surface will be 
reached, and in the three weeks’ migration through the mid- 
water the little fish will have grown from 10-11 millim. to 
17-18 millim., a very rapid rate of growth. The surface ¢ 
period lasts from 17 millim. to about 30 millim., and 
extends from the third week in May till about the second 
week in June or thereabouts, when the adult habitat is 
adopted. Here, again, im about three weeks, the young sand- 
eel grows from 17-18 millim. to about 30 millim. Sand-eels 
of larger sizes are caught at the surface, as almost everywhere, 
the universal distribution of this species being well known, so 
that the term ‘littoral’? used in ‘lable Il. merely implies 
that sooner or later, at any rate by the spawning-time, a 
migration shorewards is effected. 
I have recently worked over a number of bottles containing 
sand-eels, and have also been through a list of larval and post- 
larval fishes which appears in this year’s ‘Scottish Fishery 
Board Report.’ I have thus been enabled to have access 
* Large numbers of sand-eels 15 to 16 millim. in length are found 
amongst the pelagic ova of the food-fishes near the surface in April (vide 
M‘Intosh, Trawling Report, 1885). 
+t By “surface” is meant the upper waters. 
