6 FISHES OF ILLINOIS 



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 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 consists of microscopic organisms which are 

 carried into the pharynx 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. plane ri) 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 parasitic activity 

 intervenes between this transformation and complete sexual 

 development in typical, parasitic lampreys. That spawning 

 takes place but once and that it is accompanied by serious patho- 

 logical changes in both parents, from which they recover 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. 

 Wilder i), 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 adults 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 Germany, the French 

 regarding as an especial delicacv 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 lamprev 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 Connecticut River, though this industry 

 is now practically discontinued. 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. 



* Journ. Anat. and Physiol, norm, path., (2) XIII., pp. 612-637. 



