224 REPORT OF THE COMMISSIONERS OF 



reproductive bodies remained to be developed later. This is strong evidence of death 

 after once spawning. 



One author writes that an argument against the theory of their dying after 

 spawning can be found in the fact that so few dead ones have been found by him. 

 However, many can be found dead if the investigator only knows where and how to 

 look for them. We should not anticipate finding them in water that is shallow enough 

 for the bottom to be plainly seen, as there the current is strong enough to move them. 

 It is in the deep, quiet pools, where sediment is depositing, that the dead lampreys are 

 dropped by the running water, and there they sink into the soft ooze. Such a place 

 as this is shown in Illustration No. 12, just in line with the lower part of the fork of 

 the Y-shaped stick. It is from this spot that we dipped the pail full of debris : young 

 lampreys, dead lampreys, and dead fish shown in Illustration No. 13. Here we found, 

 later, five dead lampreys and three dead fishes. By carefully searching in the proper, 

 inconspicuous places, with suitable apparatus, we have found scores of dead lampreys. 

 However, as their bodies are very soft and boneless, and their flesh decays quite soon, 

 their remains would not long keep in any place. 



On the 8th of June we killed one hundred lampreys, and marked them by cutting 

 off their heads. They were then dropped in the shallow waters of the spawning beds, 

 in various stretches of the stream. On the following morning only six were to be 

 found in the stream, after a careful inspection from the shore, and the next day only 

 two were visible, although several unmarked lampreys were found dead. This shows 

 what a very small percentage of those that have recently died we should expect to see, 

 and also that the absence of great numbers of dead lampreys from visible portions of 

 the streams cannot be regarded as important evidence against the argument that they 

 die soon after spawning once. In the weir that we maintained in 1898, a number of 

 old, worn-out and fungussed lampreys were caught drifting down stream ; some were 

 dead, some alive, and others dying and already insensible, but none were seen going 

 down that appeared to be in condition to possibly regain their strength. 



3tractctres and Origin. 



There are many peculiar and interesting structural features shown in the lampreys, 

 but these belong to the subject of their anatomy, which we cannot take time and space 

 to discuss in the present article. Besides, we have aimed to deal here mostly with the 

 unfamiliar or formerly unknown features of their habits or life histories, and with those 

 points that are of greatest importance in connection with their economic effects, 

 which might throw light upon methods of their removal. However, attention should 

 be called to the single median nostril, and the pineal body, supposed to represent a 



