THE SAND-EEL FAMILY. 303 



absorbed, and only a trace of the oil-globule remained. The 

 gut had not yet opened posteriorly, though it was close to 

 the fin-margin. 



The later stages of the torsk have yet to be described, but 

 the materials for this purpose are too few, probably because 

 the young forms keep to the deep water. A single example, 

 10 inches long, exists in the University Museum. It was 

 captured in February, and probably was about a year old. 



The Sand-Eel Family. Ophidiidae. 



General Remarks on the Sand- Eels. 



The two common sand-eels are very closely allied, and it 

 requires a trained eye to at once distinguish between specimens 

 of the same size. As this distinction was only comparatively 

 lately understood it is not surprising that the young stages are 

 not yet clearly diagnosed. They have an economic importance 

 far out of proportion to their small size and their little-known 

 appearance. In many parts, especially on the coast of Britain, 

 the sand-eels are dug up from the sand between tide-marks 

 and are sold for human consumption ; indeed, we bear witness 

 to the very delicate dish furnished by these little fishes. They 

 are also used very successfully as bait, and it is known that 

 they form a staple article of diet to cod, whiting, mackerel, 

 salmon, and other important food-fishes. At Elie, for instance, 

 on the shores of the Forth a regular fishing for them takes 

 place in summer for bait. 



This utility of the sand-eel as a source of food to the larger 

 food-fishes is not confined to the adult, but the immense 

 numbers of larval and post-larval 'fry' also form a great 

 attraction. So much is this the case that an intimate know- 

 ledge of the life-history and habits of these fishes may at any 

 time prove of practical utility in giving the key to the migra- 

 tions of ' schools ' of larger fishes (see also Rockling). 



