127] LIFE HISTORY OF GORDIUS AND PARAGORDIUS—MAY 



INTRODUCTION 



The Gordiacea seem to have escaped the observation of the earlier 

 writers or else to have been mistaken for filariae. Meissner (1856) and 

 Villot (1874) who review the older literature, agree that the first reference 

 to the group was made by Albert the Great. Linnaeus introduced the 

 term Gordius on account of the resemblance of a mass of the worms to the 

 Gordian knot. He included in the genus the three species G. aquaticus, 

 argillaceus and medinensis, representing respectively the present families 

 of Gordiidae, Mermithidae and Filariidae, only the first of which is today 

 retained in the order Gordiacea. 



Du jar din was the first to give detailed descriptions of two species, 

 Gordius aquaticus and Gordius tolosanus, and to point out the difference 

 between Gordius on the one hand and Mermis on the other. 



Von Siebold and following him Meissner (1855) placed Gordius and 

 Mermis together to form the order Gordiacea. Meissner's work on 

 the anatomy and physiology of Gordius and Mermis is in many respects 

 an excellent production and it is inconceivable how, after such observations, 

 he could still regard the two groups as closely related. The work of Gren- 

 acher (1868) on the anatomy of Gordius was a step in the right direction. 

 He emphasized again the difference between Gordius and Mermis and 

 stated that the two could not possibly belong to the same family. 



yillot was the first to take up the study of museum specimens and 

 living material in larger quantities. His investigations were carried on 

 for a long series of years and with an earnest desire to solve the problems 

 of taxonomy, physiology and life history; but unfortunately did not con- 

 tribute much to a clearer knowledge of the group. The problem was too 

 great for the methods he employed. 



In England Baird described several species and in Germany von Lin- 

 stow added a large number of names without giving descriptions adequate 

 for identification. 



The greatest contributions to the taxonomy of the group have undoubt- 

 edly been made by Camerano, chiefly because he had at his disposal more 

 material than has ever been available to any other writer. He not only 

 described a large number of species, but subdivided the group into several 

 genera. Creplin (1847) had already established the genus Chordodes. 

 Camerano (1897) carried the division farther in separating the genera 

 Paragordius and Parachordodes from the genus Gordius. This separation 

 was made purely on external characters. Montgomery in a paper coming 

 out somewhat later also established a genus Paragordius which, so far as the 

 anatomy of the forms is known, includes the same species as does that of 



