158 Conservation Department 



VIII. THE LAMPREYS OF NEW YORK STATE— LIFE 

 HISTORY AND ECONOMICS 



By Simon Henry Gage, B. S. 



Professor of Histology and Embryology, Emeritus, Cornell University 



Part I. Life History of Lampreys : 

 Character and distribution of lampreys. 

 Coloration and distinction of sexes. 

 The three or four kinds of lampreys in New York. 

 Nest-building and egg-laying. 

 Number of eggs laid by the different forms. 

 Death of lampreys after spawning. 

 Persistence of the notochord. 



Development of the eggs and duration of larval life, transformation and 

 buccal glands. 



Brook lampreys not parasitic. 



Summary of the life history of lampreys. 



Part II. Economics of Lampreys: 

 General on economics of lampreys. 

 Economics of larval lampreys. 

 Economics of the brook lamprey. 

 Economics of the sea lamprey. 

 Economics of the lake lamprey. 

 Experiments on the predatory habits of lampreys. 

 Amount of damage done to food-fish by lampreys. 

 Ridding a lake of lampreys. 

 Summary of the economics of lampreys. 



Life History of Lampreys 



Character and Distribution of Lampreys.— The lampreys or 

 lamprey eels are aquatic animals having an elongated rounded 

 body with a tail fin and two dorsal fins, but no pectoral or ventral 

 paired fins like ordinary fishes. They have seven gills on each 

 side, each gill having a separate opening. In the adult stage they 

 have a disc-like, sucking mouth with numerous horny teeth. They 

 have no bones, but simply cartilage and connective tissue for a 

 skeleton; and are among the lowest of the vertebrate animals. 

 They are found in the temperate regions of both hemispheres, but 

 more abundantly in the northern with its greater amount of land 

 and more numerous, fresh water streams. 



Like the frogs and toads the lampreys have a young or larval 

 stage which is very unlike the adult, indeed so unlike their parents 

 that only since 1856 have scientific men known that they were the 

 young of the free-swimming lampreys. 



A young frog or toad is called a tadpole or pollywog, or some- 

 times the classical name is used and it is called gyrinus. So with 

 the lampreys, their young are called mud-lamprey or sand-lamprey, 

 and frequently in scientific writing the Greek name ammocoetes is 

 used. It is true that the larval lamprey does not look so different 

 from its parents as does the frog or toad tadpole, still the difference 

 in structure and habits of life are fully as great. 



