NO. 1573. PARASITIC COPEPODS— WILSON. 477 



The appendages are similar to those aheady described, except 

 that the swimming legs are more jilainl}^ segmented and armed with 

 larger spines. In the second and third pairs also there is a good- 

 sized spine on the l)asal joint just outside of the base of the exopod. 

 In the third legs there is the same difference in size between the 

 exopod and endopod, and the terminal joint of the latter is armed 

 with a similar large and strongly curved claw. 



Total length, 8 mm.; length of carapace on mid-line, 3.75 mm.; 

 width of same, 4.35 mm.; length of second and third segments, 1.15 

 mm.; of fourth segment plates, 2 mm.; of genital segment, 3 mm.; 

 width of latter, 3 mm. 



Color a uniform ^^ellowish wliite, similar to that of the female and 

 male alread}^ described. 



{muricata, with sharp ])oints or spines.) 



This species is confined almost exclusively to the Sunfish, so that 

 Poche's generic name is eminentl^T^ fitting. But while Cecrops is 

 usuall}^ found upon the gills, the present species frecjuents the outer 

 surface of the body, the vicinity of the anal fm being a favorite local- 

 ity. It is fiu'thermore gregarious in habits, and from ten to twenty 

 individuals gather together in bunches. The combineti laceration 

 of their sharp claws and probosces witliin so small an area quickly 

 penetrates even the thick skin of the Sunfish. The groups of para- 

 sites thus come to lie m the bottom of depressions or pits wliich are 

 eaten through the skin of the fish and into the raw llesh beneath; 

 the edges of the pits are raised slightly above the surroiuiding surface 

 and calloused. (See A. Scott, 1892, p. 266.) 



With the claws of their second antenna and second maxillipeds 

 sunk deeply into the flesh of their host in the bottom of these pits, 

 they are secure from friction and many of the other evils that come 

 from living on the outside of the host's body. 



But wliile thus protected from some dangers, their fixed habit 

 renders them peculiarly liable to others. Chief among these is the 

 fact that their bodies, and especially the chitinous plates which cover 

 its dorsal surface, furnish admirable anchorage for maiiy of the other 

 fixed forms, animal and vegetable, which live in the ocean. It thus 

 happens that we frecpiently fuid the dorsal surface of one of these 

 parasites covered with alga^, infusoria, hydrozoa, or even barnacles. 

 Of the latter the striped barnacle, which is found also upon Pennella, 

 is the most common, and specimens of Orthagoriscicola may be found 

 canying a huge Lepas larger than their own bodies. Two such 

 specimens are figured by Hoeven in the paper alread}^ cited, 1857, 

 Plate IV, fig. 10. 



Although this can not be regarded as a case where ''Greek meets 

 Greek," since the Lepas is not in any sense a parasite, yet the fasten- 

 ing of its heavy weight upon the back of the copepod must be a sore 

 burden to the latter. 



