PARASITIC COPEPODS—CALIGID.E— WILSON. 



499 



twenty in number (fig. 6). The bases of the mandibles are attached 

 just inside the lateral chitin rods of the lower lip, and are connected 

 with the ventral surface of the carapace by stout muscles. There are 

 no traces of mandibular palps. 



The first maxillse (rax', tigs. 4 and 5) are situated near the lateral 

 margin of the carapace, just outside of, and a little posterior to, the 

 bases of the second antenna?. Each consists of a single joint in most 

 of the species, but of two joints in a few species of Caligus according 

 to the descriptions given. In 

 both sexes they are swollen at 

 the base and taper toward the 

 tip; in the female they are short 

 and blunt and apparently of no 

 service. 



In the male they are much 

 longer and taper to a slender, 

 sharp point at the apex; each 

 maxilla is also curved over 

 toward its fellow on the oppo- 

 site side and thus forms a claw 

 similar to that on one of the 

 second antenna? (fig 5). And 

 their function would seem to 

 be similar, although we must 

 remember that they are shorter 

 and Aveaker than both the sec- 

 ond antenna 1 and the second 

 maxillipeds and so could not 

 reach the host's body until after 

 these others had been buried in 

 the skin. Possibly they may 

 serve in both sexes to irritate 

 tin 1 wound and so stimulate the 

 flow of blood. In some species 

 <>f Caligus and Lepeophtheirus 

 two minute setse arc attached 

 to the basal part of each max- 

 illa which A. Scott considers to represent the exopodite or palp 

 (c\ tig. 7). 



The second maxilla' (nix", tig. 4) are placed at the sides of the mouth 

 just outside of the suctorial tube. Each is made up of a single joint, 

 stout at the base and slender toward the tip. 



In GaUgu8 and closely allied genera the terminal portion is undivided 

 while in Lepeophtheirus and its near relatives it is bifurcated. 



Fig. 4b.— Ventral surface and appendages of an 

 adult male Lepeophtheirus edwardsi. (For 

 lettering see Fig. la.) 



