476 Simon Henry Gage 



the proportion given by Thompson, i. e., three or four white 

 ones to one red one. In my own observations the red ones 

 were always in excess of the white ones. (See table above). 



The amoeboid movements of the wliite ones are striking and 

 vigorous in both larva and adult, but as a rule the motion does 

 not begin immediately after the preparation is made, It is 

 usuall}- at its greatest about half an hour after the blood is 

 obtained. 



SUMMARY AND GENERAL CONCLUSION. 



1. Two species of lampreys inhabit the chain of lakes in 

 western New York. 



2. One, the brook lamprey (^Petromyzon or Amviocceies 

 branchialis) is small in size, few in numbers and short-lived, 

 in the adult stage. It is not known in North America outside 

 the Mississippi Valley except in the Cayuga L,ake basin. It 

 is probably widely distributed, but from its small numbers and 

 inconspicuous coloring, it has been overlooked (Plate IV, pp. 



436, 452). 



3. The other, the lake lamprey Petroinyson iinicolor or do7'- 

 satus), is of large size, is in great numbers and lives a para- 

 sitic life in the lakes for a period of two to three and one-half 

 years, and perhaps longer (Plate I, III, pp. 431, 445, 452). 



4. The lake lamprey from the structure and arrangement of 

 its teeth is hardly to be distinguished from the true anadro- 

 mous sea lamprey, but judged by the physiological test of nat- 

 ural interbreeding it must be considered as specifically dis- 

 tinct (Plate VI, p. 426). 



5. Both species have a larval stage and a metamorphosis at 

 the end of from two to four years. Thus agreeing with the 

 Petromyzontidae wherever thoroughl}' studied (Plate III, IV, 

 VI, VIII, pp. 449, 452). 



6. The proportions of parts of the body with the two sexes 

 of the lake lamprey, are very unlike and mutually interchange 

 between the ordinary non-breeding and the breeding season. 

 (See Table and p. 431). 



7. In both species there are striking atrophies and hyper- 

 trophies at the spawning season (Plate III, IV, VII, p. 438). 



8. Both species construct similar nests for the deposit and 



