304 .MARKETABLE BRITISH MARINE FISHES 



independence. The most conspicuous differences are the following : 

 In the larger kind the projection of the lower jaw is greater ; 

 there are two strong teeth in the roof of the mouth, on the bone 

 called the vomer ; and the commencement of the dorsal fin is 

 behind the hinder extremity of the pectoral or breast fin. In 

 the smaller kind the two teeth in the roof of the mouth are 

 absent, and the commencement of the dorsal fin is so far forward 

 that the pectoral extends behind it by one-third of its own 

 length. Both kinds are rare in the Mediterranean, where a third 

 species occurs, but extend all along the European shores to the 

 Arctic Ocean. They are not found on the American side, where 

 other species of sand-eel take their place. 



Sand-eels feed on small sprats as well as on the young of 

 their own kind, but it seems likely that their food consists partly 

 also of small Crustacea. 



Breeding. The spawning of the lesser sand-eel has been 

 investigated successfully in Scotland, but a complete description 

 of the eggs and their development has not been supplied. 

 This species was found to be spawning in June and July, 

 especially in the latter month, at the mouth of the Tyne, in 

 Haddingtonshire. The spawning fish were only obtained from 

 the sand at or below the low water-mark of spring tides, so that 

 the eggs are not left long out of water, although when not 

 spawning the fish are often found buried far above low water- 

 mark. The eggs were artificially fertilised and found to be 

 globular and slightly adhesive. Under the natural conditions 

 they attach themselves to the grains of sand at the surface of the 

 ground and there develop. The attachment is not very firm, and 

 the egg-membrane is easily burst. The egg of the larger species 

 when ripe but not fertilised was "j mm. in breadth, the yolk was 

 granular, and there was a large single oil-globule of a green 

 colour. In the smaller sand-eel the perfectly ripe eggs have not 

 been described, but are presumably similar. 



The development of the eggs of the lesser sand-eel occupied 

 ten days in July, and the larvae when hatched were 3 mm. to 3-5 

 mm. in length (y 1 ^ to T W inch, i.e. less than -^ inch). The absorp- 

 tion of the yolk also occupied ten days. No figures of the 

 developing eggs or newly-hatched larvae have been published. 



Certain very slender larvae, 5 to 6 mm. long Q inch), obtained 

 regularly in the bottom tow-nets in March, at St. Andrews, arc 



