1 62 BRITISH FRESHWATER FISHP^S 



sieves of haircloth, or even with a common basket, 

 and were fried in cakes or stewed and considered 

 delicious, whilst Thompson wrote of the Bann that 

 in the early summer the river was black with 

 thousands of young Eels 3 or 4 inches long, and 

 that hay-ropes were suspended over the rocky parts 

 to help them in their ascent. 



As has already been mentioned, our knowledge 

 of the life-history of the Eel has been greatly in- 

 creased by the work of two Danes, Petersen and 

 Schmidt. It is to a third Danish zoologist, Gemzoe, 

 that we are indebted for the determination of the age 

 and rate of growth of the Eel. He has shown that 

 the elvers, which reach Denmark about May, grow 

 slowly and are less than 4 inches long after a 

 year spent in fresh water ; during the next summer 

 they attain a length of about 5 (4 to 7) inches ; 

 in the third summer this length is increased by 

 about 4 inches, and it is in this season, when 

 they are a little more than 7 inches long, that 

 scale formation begins. 



When a scale is examined under the microscope 

 the outer surface is seen to be studded with little 

 calcareous buttons, which are arranged in zones 

 or rings parallel to the edges, and are separated 

 from each other by narrow rings occupied only 

 by the fibrous ground-substance of the scale. This 

 structure is due to the fact that the Eel feeds and 

 grows actively in the summer months only, and 

 the zones are annual rings formed during the 

 summer, whilst the narrow interspaces represent 

 the growth of the scale during the colder months. 



Scales are first formed on the middle of the 

 side, and if scales from this region be examined their 



