PETROMYZOXIDvE THE LAMPREYS / 



and flesh. Their hold is probably seldom loosened by any fish, 

 unless by accident. The power of suction exerted by the buccal 

 funnel, without the aid of the formidable armature of cusps, is 

 such as to require considerable force* to loosen it. Lampreys 

 most frequently attach themselves to the side of a fish under the 

 pectoral fin. Scaleless fishes, such as catfish and spoonbills, and 

 the relatively sluggish soft-rayed and soft-scaled fishes, such as 

 suckers and buffaloes, are much more subject to their attack 

 than the more alert and better protected spiny-rayed fishes. The 

 listf of species infested in Cayuga Lake, New York, by the land- 

 locked marine lamprey (Petromyzon marinus unicolor) included 

 practically all the fresh-water species which were not too small. 

 The brown bullhead (Ameiurus nebulosus) suffered most severely, 

 and the common fine-scaled sucker (Catostomus commersonii) 

 next. Black bass were rarely attacked. The period of the 

 lamprey's most destructive activity was in early spring — February 

 and March. 



Whether adult lampreys take any food except the flesh and 

 blood of the fish upon which they prey is not certainly known. A 

 common statement of the earlier writers that they feed on worms, 

 insects, and decaying animal matter, probably rests mainly on 

 hearsay and needs confirmation. Stomachs of Cayuga Lake 

 lampreys examined by Dr. Gage in 1893 and 1898 contained 

 nothing but blood and fragments of muscle. The presence of 

 pieces of various small animals in the stomachs of lampreys, which 

 has been only occasionally reported, is probably due to the com- 

 plete perforation of the body wall and intestine of the infested 

 fish. The charge sometimes made that lampreys eat the eggs of 

 fishes has not been substantiated. 



The breeding habits and development of the brook lampreys 

 of both America (Lampetra wilderi) and Europe (L. planeri) have 

 been studied in detail by various workers. The females spawn 

 in shallow water, and, as a rule, where there is some current over 

 pebbly or stony bottom near the headwaters of a stream. During 

 the spawning process the females cling with their oval mouths to 

 pebbles or stones, with the body streaming in the current, and 



* Recent experiments by Miss Dawson (Biol. Bull., IX., 1905, pp. 1-21, 

 91—111) have shown that the funnel of a dead brook lamprey {Lampetra wilderi) 

 becomes firmly attached to a perfectly smooth surface when merely pressed 

 against it with the fingers. Her experiments also indicate that a lamprey is 

 able to glide about over the surface of its host without loosening its hold. 



t H. A. Surface, Fourth Ann. Rep. Comm. Fish, Game, and For., X. V., 1898, 

 PP. 191-245. 



