196 



TRANSLATIONS. 



On Gyrodactylus elegans, Nordmann. 

 By Br. G. R. Wagener. 



(From Reichert and DuBois Reymond's ' Archiv. f. Anat.,' 1860, p. 768.) 



The curious phenomena connected with the reproductive 

 process in Gyrodactylus render it a most interesting object 

 of study to the physiologist. Till very lately, we are not 

 aware that it was known to occur in this country ; but 

 Mr. C. L. Bradley having shown that one, if not two, species 

 are very abundant on fish taken from the ponds on Hampstead 

 Heath,"^ it will probably be found elsewhere. We have 

 therefore thought it might be interesting to those of our 

 readers who may meet with it, and be disposed to investigate 

 the structure and development of this remarkable creature, 

 to have before them the excellent account of Gyrodactylus 

 given by Dr. Wagener, who has added so much to our know- 

 ledge of the subject in the present paper, which we have 

 translated in all important particiilars very nearly in its 

 entirety. 



Since the discovery, by Nordmann, of this remarkable 

 parasite on the gills of the perch and other fish, it has been 

 subjected to fresh examination by Creplin, Dujardin, and 

 more recently by Von Siebold, the latter of whom more 

 particularly has confirmed Nordmann's representations of 

 the organization, and added observations of the most sur- 

 prising nature as to the development of Gyrodactylus elegans. 



He showed that a young Gyrodactylus arises in the interior 

 of the parent animal from a self-dividing cell, that it becomes 

 fully developed in the same situation, and whilst still itself in 

 the embryo condition, produces a second off^spring within 

 itself. To these observations he added further statements 

 respecting the organization of the animal, and especially 

 pointed out the absence of any spermatic organs. 



From the latter circumstance Von Siebold felt himself 

 compelled to regard Gyrodactylus a& a. ^'nursing'' animal; 

 and in accordance with this view, he named the cell from 



* ' Journal of Proceedings of Linnean Society,' vol. v, pp. 209 and 257. 



