SYSTEMATIC ARRANGEMENT. 27 



more or less permanently fixed to their host. This 

 group of parasites was arranged by M. Edwards into 

 three families viz., the Chondracanthiens, the Lerneo- 

 podiens, and the Lerneoceriens. The Chondracan- 

 thiens " are fixed by the aid of stout foot-jaws armed 

 with strong hooks." The Lerneopodiens have the 

 second maxillipeds modified, and furnished, at their 

 extremity, with a chitinous horn-coloured process, 

 which, penetrating the gills, gill-covers, or some other 

 part of the fish, forms a permanent attachment to it, 

 while the head of the parasite is free and apparently 

 possesses to a small extent a certain freedom of move- 

 ment. In this family the male is very small and is not 

 attached to the fish, but is usually found adhering to 

 the body of the female, two or three males being some- 

 times found on the same female. The third family of 

 M. Edwards, the Lerneoceriens, are fixed to their host 

 by having the head, sometimes with its appendages, 

 buried in its tissues. This arrangement of Milne 

 Edwards, slightly modified, was adopted by Dr. Baird 

 in his ' British Entomostraca,' and is to some extent 

 still adhered to. 



Various attempts have been made to frame a classifi- 

 cation of the Copepoda which would include the para- 

 sitic and semi-parasitic forms, but, with the exception 

 of that of Professor G. 0. Sars, they have proved 

 more or less unsatisfactory, and therefore, as already 

 stated, we have, as regards these parasitic species, 

 adopted the division proposed by Sars. Referring to 

 the various attempts at classification, C. B. Wilson, 

 in a recent article on the subject, remarks : " It 

 requires about as thorough a knowledge of the Cope- 

 poda to select intelligently from these various schemes, 

 backed as they are by competent authority, as it 

 would to construct an original scheme. Indeed most 

 authors have apparently found the latter the easier, 

 since each has propounded a scheme of his own."* 



* "The Classification of the Copepods," by C. B. Wilson, in ' Zool. 

 Anzeiger,' vol. xxxv, No. 20, 26th April, 1910, p. 611. 



