310 THE SAND-EEL FAMILY. 



it covers the sandy shallows with innumerable hosts, and later, 

 in the surface-water, before assuming the adult habit 1 . 



It is instructive to compare the change of habitat of the 

 growing plaice and that of the sand-eel. In the former, life is 

 commenced in the surface-water, with its bright surroundings 

 of sunlight, and as the embryo advances in its development it is 

 drifted towards the shore. Here the little larva, set free from 

 its prison, migrates gradually but surely to the bottom in 

 shallow water. With increasing size a slow seaward journey is 

 commenced, so that keeping the bottom, greater depths are 

 reached. In the other case, the embryo embarks upon existence 

 (in the winter-spawning) in fairly deep water, and embedded 

 in the dark still sand. From this secure retreat the larval 

 form emerges and with increased size it works its way upwards 

 to the light and warmth, and eventually disports itself in the 

 surface-water, a prey to many a foe. 



Many remain in the surface-habitat, which has its drawbacks, 

 as shown by the long line of pelagic organisms sometimes 

 thrown up by a stormy sea upon the shore, whilst others 

 (Plate XII, fig. 9) pursued and hunted everywhere, bury them- 

 selves in the sand, whence they are withdrawn by man to serve 

 his purposes as food or bait. 



From the fact that very young sand-eels are found in 

 multitudes at the surface in the offshore waters, it is clear 

 that spawning in the sand also takes place there. Indeed, the 

 ubiquitous habits of the species would render such probable. 

 During the winter, besides, the eggs would be safer in deep 

 water than in shallow water even in the sand. The use of 

 the sand-eel net in January in the estuary of the Eden gave 

 only young forms of 2 inches, whereas the same net in summer 

 and autumn captured numerous adults as well as intermediate 

 stages. The adults were ripe in January, but whether in the 

 sand or in the deeper water of the bay or neighbourhood was not 

 ascertained. 



The contrast in the life-history of two such common forms 

 as the plaice and the sand-eel is thus fraught with meaning 

 and is reflected in the form, shape, and colour of each at 

 1 A. T. M. Annals Nat. Hint. October, 1895. 



