FISHERIES, GAME AND FORESTS. 207 



by enemies during the night — by the presence of a school of minnows in the fresh 

 beds, while the older beds, with the eggs covered deeper and commencing to hatch, 

 would have no minnows over them. By digging in the sand and determining the 

 stage of development of the eggs or larvae, it is possible to ascertain how long the 

 beds have been deserted. Although it is well known in some places that young 

 lampreys (often called "Sand Lampers") are excellent bait for certain voracious 

 fishes, yet they are not used much in this region for that purpose; and, although the 

 piscivorous fishes readily take larval lampreys when they can get them, it cannot be 

 said that the larger fishes naturally destroy many lampreys in this stage, as this is 

 manifestly rendered impossible by the habitat of the young marsipobranchs. We 

 have seen a bowfin (Amia calvd) eat an adult lamprey in an aquarium, but these con- 

 ditions were too unnatural to justify us in the conclusion that in untrammeled nature 

 fishes destroy adult lampreys. We have never known or heard of a definite 

 example of this. 



6. Fungus. The attack that attends the end of more lampreys than does any other 

 is that of the fungus {Saprolcgnia sp.). This looks like a gray slime, and eats into the 

 external parts of the animal, finally causing death. It covers the skin, the fins, the 

 eyes, the gill pouches and all parts, like leprosy. It starts where the lamprey has been 

 scratched or injured or where its mate has held it, and develops very rapidly when 

 the water is warm. It is found late in the season on all lampreys that have spawned 

 out, and it is almost sure to prove fatal, as we have repeatedly seen with attacked fishes 

 or lampreys kept in tanks or aquaria. With choice aquarium fishes a remedy, or at 

 least a palliative, is to be found in immersion in salt water for a few minutes or in 

 bathing the affected parts with listrine. Since these creatures complete the spawning 

 process before the fungoid attack proves serious to the individual, it can be seen that it 

 effects no injury to the race, as the fertilized eggs are left to come to maturity. Also, 

 as it is nature's plan that the adult lampreys die after spawning once, we are convinced 

 that death would ensue without the attack of fungus; and in fact this is to be regarded 

 as a resultant of those causes that produce death rather than the immediate cause of it. 

 Its only natural remedy is to be found in the depths of the lake (450 feet), where there 

 is a uniform or constant temperature of about thirty-nine degrees Fahrenheit, and 

 where the light of the noonday sun penetrates with an intensity only about equal to 

 starlight on land on a clear but moonless night. 



As light and heat are essential to the development of the fungus, which is a plant 

 growth and properly called a water-mold, and as their intensity is so greatly diminished 

 in the depth of the lake, it is probable that if creatures thus attacked should reach this 

 depth they might here find relief if their physical condition were otherwise strong 

 enough to recuperate. However, we have recently observed a distinct tendency on the 



