352 BULLETIN OF THE UNITED STATES FISH COMMISSION. 



a half turn of his body, brings his abdominal aperture close to that of 

 the female, a part of her spawn may be seen flowing forth in a clear, 

 semi-opaque flood. This action is repeated until the female has deposited 

 all of her eggs. The young lampreys, when hatched, burrow in the 

 mud. They require a period of four or five years before they reach the 

 size of twenty centimeters." 



It is now believed by many of the best European authorities that the 

 parent lampreys die after spawning. 



The development of the lamprey is exceedingly remarkable. It was 

 first worked out thoroughly by Prof. August Muller, in 1856.* 



The young was formerly considered to be a member of a distinct genus, 

 Ammoccetes. The young of the brook lamprey, P. planeri, which in a 

 general way correspond to those of other species, are thus described by 

 Professor Benecke : 



" They are tawny yellow, without any trace of silvery hues, and have 

 half-moon shaped toothless mouths, not intended for suctorial uses. 

 Their small eyes are hidden deeply under their skins, and hardly visible. 

 Their gill-openings lie in a deep furrow. The head is small and pointed, 

 and the fins continuous." 



It is a curious fact that as early as 1866 Leonhart Boldner, of Stras- 

 bourg, investigated and thoroughly understood the development and 

 metamorphoses of the lamprey, as is indicated in the following para- 

 graph translated from his work upon the water-birds, fishes, and other 

 aquatic animals of Strasbourg : 



" From August to December lampreys with eyes are not often seen 

 and are rarely taken, but blind lampreys are found throughout the entire 

 year. The lampreys with eyes and the blind lampreys are all of the 

 same kind, for the young from the very beginning are all blind, and 

 bury themselves at once in the mud as soon as they make their escape 

 from the eggs. The blind lampreys develop no eggs until they develop 

 their eyes."t 



Like the eel, the lamprey was formerly believed to be hermaphrodite.^ 



So far as I am aware few observations are on record which indicate 

 the date of the spawning of the lampreys in this country. Wittmack, 

 in his excellent work upon the Fishery Statistics of Germany, states 

 that P. marinus spawns at Hameln in June, and in the Ehine at Zurich 

 in March and April; P. Jiuviatilis in various parts of Northern Germany, 

 chiefly in March, April, May and June, though in the Kurisches Haff 

 also in November, December, and February. In Bavaria their spawn- 

 ing season is from March to June ; in Austria, in April and May ; and 

 in Switzerland, in March and April. P. planeri is said by the same 

 author to spawn in Pomerania in May, in the Rhine provinces in March 

 and April, in Hanover in May and June, in Gotha in March and April, 



"Miiller's Archiv fur Naturegeschichte, 1856, p. 325. 



tSeo Vou Siebold, Siissivasserfische Mittel-Europas, p. 378. 



J Sir Everard Home in Philosophical Transactions, 1815, p. 266. 



