PETROMYZONID.S: THE LAMPREYS 7 



of the formidable armature of cusps, is such as to require con- 

 siderable 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 in- 

 fested 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 prob- 

 ably due to the complete perforation of the body wall and in- 

 testine 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 lam- 

 preys 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 are clasped at the nape by the suctorial 

 disks of the males. The young lampreys burrow in the mud as 

 soon as hatched. They are sightless at first, the eyes being 



* 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. 



f H. A. Surface, Fourth Ann. Rep. Comm. Fish, Game, and For., N. Y., 1898, pp. 191-245. 



