STUDIES ON PARASITIC COPEPODS OF THE 

 GENUS SALMINCOLA^ 



Oregon- Agricultural College, Corvallis, Oregon 



The parasitic copepods afford a very interesting group 

 of animals for the biologist. Not only do these organisms 

 offer many fnsciiintino- jiroblems for the pure scientist, 

 but from tlie < oimii(M( ial standpoint they are extremely 

 important a> | (ara-ites of our food and game fishes. 

 There is every degree of parasitism amongst these Crus- 

 tacea, from those which spend a very small portion of 

 their existence as parasites to those whicli are parasitic 

 throughout almost their entire life. My own studies, 

 covering a period of nearly ten years, have been confined 

 to some of the most highly specialized members of the 

 latter group, lielonging to the genus Salmincola of the 

 family Lcrn cr o p o d I d (C . 



Tlic 'Sdlntiiicohi are parasitic on the Salmonidce, 

 wliicli iiicliKle such iitipoi'tant fishes as salmon, trout, lake 

 hei'i'iiiu' and wliitclish. Tliese copepods are all built on 

 a similar plan and can be easily recognized. The adult 

 female- arc tlic oiio whicli are usually encountered, and 

 these ma\- be attached to the delicate membranes of the 

 gills, gill chambers, (ins and mouth of the host. Here 

 they hang on and are supplied with a constant stream of 

 fresh blood, which serves as their sole food. 



These adult copepods can be readily seen with the 

 naked eye. They ai-e ([uite large, measui-ing a few milli- 

 metei'> in length, and are yel|owi>h-whi1e in color. An- 

 teriorly tliey are fasteiUMl to the host by means of two 

 sec.iul maxilhe and a chitini/e<l hnlla. This last named 

 strnctnre i- imhedded in the tissues of the host. Pos- 

 terioi-lx^ .'.ich tenia le jiossoses a pair of slender freely 



1 DollvorcMi l.eforo tlu' Biological Club, Oregon Agricultural College. 



