8 FISHES OF ILLINOIS 



deeply buried beneath the skin. The mouth is toothless, and 

 is not circular, like that of the adult, but the upper lip is of a 

 squarish, hood-like form, and the lower one is much shorter 

 and included within it. The food of the larval lamprey con- 

 sists of microscopic organisms which are carried into the phar- 

 ynx by currents of water produced by ciliary action. It is an 

 interesting fact, first ascertained by Alcock*, that during the 

 larval period the epidermis of the European brook lamprey (L. 

 planeri) has the power of secreting a digestive ferment which 

 protects the burrowing larva from the injurious action of fungi 

 and bacteria. The length of the larval period is from 3 to 5 

 years. The period of transformation, during which the eyes 

 move to the surface, the suctorial disk replaces the hood, and 

 the teeth are formed, is 7 or 8 months September to April 

 according to Gage. It, is not known how long a period of para- 

 sitic activity intervenes between this transformation and com- 

 plete sexual development in typical, parasitic lampreys. That 

 spawning takes place but once and that it is accompanied by se- 

 rious pathological changes in both parents, from w r hich they re- 

 cover with difficulty if, indeed, at all, is a belief long generally 

 held. This is known to be true of the small American brook 

 lamprey (L. wilderi), in which spawning and death are said to 

 follow so soon after the transformation that the parasitic stage 

 appears to be quite passed over in the life cycle, the adultfe not 

 taking food of any kind. 



The economic importance of lampreys as food for man and 

 as bait, especially in the European countries, has been and is 

 to-day considerable. In the earlier centuries they were highly 

 esteemed as an article of food in England, France, and Ger- 

 many, the French regarding as an especial delicacy stewed 

 lampreys which had been first drowned in wine. In England 

 to-day both the fresh-water and the marine lampreys hold a 

 place among edible fishes, and in Russia extensive lamprey 

 fisheries were still carried on along the Volga in 1873. Nets 

 and wicker traps are used in the lamprey fisheries. As late as 

 1880 an extensive fishery was carried on along the lower Con- 

 necticut River, though this industry is now practically discon- 

 tinued. Lampreys pickled and put up in tins may be obtained 

 of our larger American dealers in fishery products, and are said 

 to be of very fine flavor. 



* Joum. Anal, and Physiol. norm. path. (2) XIII., pp. 612-637. 



