324 TRANSACTIONS OF THE [mAY 10, 



time at least carry stones to] a particular part of the nest, the 

 rest of the spawning party would be as diligently carrying them 

 in other directions, often borrowing their neighbors' supplies. 

 Their common result, however, was to stir up the sand and to 

 cause the eggs to be speedily hidden. Stones were collected 

 without apparent regard to the direction of the water current. 

 Gage notes that the lampreys do not join forces to move a large 

 stone. And the present writers, confirming this observation, 

 add that they show a surprising lack of judgment as workers. 

 Their immediate mission is to move stones, and this they do with 

 greater energy than discretion ; they occasionally fasten to rocks 

 of great size and do Iheir best to transport them, turning on 

 their sides and struggling violently. An example of this wasted 

 effort is seen at the right of the plate. 



Usually, in such a case, the lamprey, finding that its first at- 

 tempt does not stir the rock, will relax its hold and proceed to 

 the next stone with the same, or perhaps better results. Some- 

 times, however, as if less easily convinced, it will retain its hold, 

 rest a moment, then recommence the struggle. In one case, a 

 single lamprey, remaining in the nest, tried again and again to 

 move objects which were out of all proportion to its efforts, in- 

 stinct appearing to lead it to seize any rock surface which af- 

 forded him a good attachment, but to avoid at once reattaching 

 in case the stone could not be moved. It seemed, therefore, an 

 evidence of weak memory when in the next circling around the 

 nest the attempt would be made to move the same stones. On 

 another day, similar actions were observed in the case of a 

 solitary male, who for several hours busied himself in a very 

 aimless way, sometimes taking stones from one side of the 

 nest and depositing them on the other, sometimes reversing 

 the process as if forgetful. 



The spawning was observed on April 16th. The eggs col- 

 lected on that day from the sand of the nest were of such a stage 

 that they must have been deposited the same morning. On this 

 day about twenty-five lampreys were captui-ed. On April 18th, 

 nine more specimens were taken but no spawning observed. 

 Some of these latter lampreys were found in another gravelly 

 section of the brook nearly a mile to the northward. Ten days 

 later, no lampre3's could be found, nor was a fourth search more 

 successful on May 5th. 



PLATE XXVII. 



The spawning of the Brook Lamprey, Petromyzon wilder i, Gage. From 

 drawing made at Lincoln Park, April 16, 1897, by Bashford Dean, x i V. 

 pp. 321-323. 



