9 
II. -THE AGE AND GROWTH OF SOME EELS FROM 
A SMALL WORCESTERSHIRE POND. 
By Professor A. Gandolfi Hornyold, D.Sc., F.R.M.S. 
( Bead December 21, 1921.) 
Eight Text-Figures. 
As far as I know, the only indications as to the growth of the eel 
in the British Isles are to be found in the work of K. Marcus, 
who examined eels from the Severn and the Clare in Ireland. 
Before the war large quantities of elvers were yearly exported 
to Germany to increase the eel supply in their waters, and Marcus 
studied their growth, showing the remarkable success of this 
experiment in various cases. 
The life-history of the eel is as follows : Schmidt has proved 
that the eel spawns in the Western Atlantic, and the first larval 
stage, the Leptocephalus, has more or less the form of a leaf, and 
is quite colourless and transparent. 
During its migration across the Atlantic, carried by the current 
of the Gulf Stream, a metamorphosis takes place, and when it 
arrives on the coasts of Europe the Leptocephalus has been trans- 
formed into a transparent colourless elver. 
The elvers appear at the mouths of rivers during the winter 
months in enormous quantities, and in some countries are greatly 
appreciated as food,, e.g. on the north coast of Spain, where the 
elver fishery is of great importance. 
Soon after its arrival on the coast pigment develops, first 
along the sides disposed in chevrons, then the lines double and 
become confused, and the chromatophores form a homogeneous 
field on the body. At the same time the elver becomes more and 
more greenish and opaque, and when the development of the pig- 
ment is ended the transparent colourless elver has become a small 
eel, which now begins to grow. 
It is curious that twice during the early life of the eel a 
reduction in length and volume takes place — once during the 
metamorphosis of the Leptocephalus to the elver, and again during 
the development of the pigment of the elver. The young eels 
are called yellow eels because of their ventral colour ; the back is 
greenish, and the colour can vary greatly. 
After a number of years which may have been spent in fresh 
water in estuaries or lagoons near the sea, or even in the latter, as 
