462 Simon Henry Gage 



of some kind could be constructed at slight expense. If this 

 could be continued for three to four years in all the lakes and 

 in the Oswego River, the race could be extinguished and the 

 lake wholly freed from their devastations. So vulnerable 

 is this point in the lampreys defenses, that even in great 

 rivers, where dams exist, the fish-ways could be utilized 

 to free the river of lampreys as well as to allow the more 

 valuable food fishes to run up and spawn. To be sure, in the 

 Merrimac and Connecticut rivers the lampreys have been 

 largely utilized for food, but if one considers the damage 

 these monstrous parasites must do to the ocean fishes it will 

 be seen that too dear a price is paid for the food they 

 furnish. It seems to the writer that from every economical 

 standpoint it would be advantageous to rid the world entirely 

 of the lampreys. It would certainly be greatly to the ad- 

 vantage of the fisheries of the State of New York if all were 

 destroyed. Naturally, however, the student of biology must 

 mourn the loss of a form so interesting and so instructive. 



RESPIRATION AND THE RESPIRATORY MECHANISM IN THE 

 LARVA AND IN THE ADULT. 



In the lampreys, the respiration is wholly aquatic. They 

 do not come to the surface and take in air as do many fishes. 

 As the dissolved oxygen is only 6 cubic centimeters in i ,000 c. c. 

 of water, while in the air there are 209 c.c. of oxj^gen in 1,000 

 CO. of air, it follows that an animal like the lamprey with a 

 purely aquatic respiration must either be very sluggish, or a 

 very perfect respiratory mecha?iisnt must be present in order 

 that it may obtain the needed oxygen from the meager supply 

 in the water. In the lamprey there is a very perfect respira- 

 tory mechanism. If one considers also the ease and com- 

 pleteness with which the carbon dioxid is eliminated in 

 aquatic respiration, and the fact that with the lamprey, from 

 its habits, only occasionally are great exertion and rapid 

 movement necessary, as in searching for prey and in spawn- 

 ing, with the attendant nest building, it will be seen that the 

 lamprey is very well off for an animal with aquatic respira- 



