FISHERIES, GAME AND FORESTS. 203 



of bait. While it would be quite impossible to hope to exterminate them by digging* 

 up all the young lampreys in the sand, their common use by fishermen would be 

 effective in reducing their numbers. 



Some writers have called the immature stage of the lamprey the "Ammo- 

 ccetes Stage," because the generic name Ammococtes was first given by Cuvier to an 

 immature European lamprey in 181 7. We cannot see why the term should be made 

 an adjective and continued as a common word. 



In the latter part of the fall the young lampreys metamorphose and assume the 

 form of the adult. They are now about six or eight inches long and differ greatly 

 from their appearance and condition when younger. The segmented condition of the 

 body disappears. The eyes appear to grow out through the skin and become plainly 

 visible and functional. The mouth is no longer filled with vertical membranous sheets 

 to act as a sieve, but it contains nearly one hundred and fifty sharp and chitinous 

 teeth, arranged in rows that are more or less concentric and at the same time 

 presenting the appearance of circular radiation (see illustrations Nos. 3 and 4). 

 These teeth are very strong, with sharp points, and in structure each has the 

 appearance of a hollow cone of chitin placed over another cone or papilla. A little 

 below the center of the mouth is the oral opening, which is circular and contains a 

 flattened tongue which bears finer teeth of chitin set closely together, and arranged in 

 two interrupted (appearing as four) curved rows extending up and down from 

 the ventral toward the dorsal side of the mouth. Around the mouth is a circle 

 of soft membrane finally surrounded by a margin of fimbriae or small fringe. This 

 completes a wonderful and perfect apparatus with which the lamprey attaches itself to 

 its victims, takes its food, carries stones, builds and tears down its nest, seizes its mate, 

 holds itself in position in a strong current, and climbs over falls. (See the interesting 

 article by Dr. H. M. Smith, on " The Three-toothed Lamprey," in the Scientific 

 American for April, 1900.) 



The Adult (see illustration No. 1, a and b). It is not known how long the 

 lamprey lives as an adult in the lake before it goes up stream to spawn, but this 

 must be at least two years, probably three. Here is another very important feature 

 that should be determined, but can be worked out only by very careful biological 

 work and the proper equipment. We know that during the spring time when there 

 were many adult and ripe lampreys on the spawning beds in the stream, we 

 have caught others that were adult but not sexually mature, feeding on the blood 

 of fishes in the lake. Having reached the lake in the form of the fully grown 

 lamprey, they are, of course, ready to adapt themselves to the changed condition 

 and assume changed habits. The most prominent economic feature in the entire 

 life history of these animals is their feeding habits in this stage, their food now 



