PA RASITIC COPEPODS—CALiaiD.?:— WILSON. 



537 



through them. On either side at the center are two large spots of the 

 pigment, which characterizes the particuhir species. This varies 

 decidedly in color and pattern in the diti'crent species tlius far exam- 

 ined and will probal)ly furnish a useful means of identification. 



There are otlier much smaller spots of the same pigment, which vary 

 somewhat in location in the ditferent species, but are usually found, 

 one on either side, close to the posterior end of the body, and a median 

 unpaired spot just al)Ove the eye. 



Of the appendages the first antennre are uiiiramous and terminate 

 in two long plumose seta?,. They are often carried close together and 

 pointing straight forward in front of the nauplius. The second 



Fig. 37.— Early nauplius of Caligus bonito, dorsal view; pigment cinnamon brown in a 

 continuous line around the margin of the body. 



antenntc and mandibk's are l)iramous, the exo})od four-jointcHl. each 

 joint bearing a long plumose seta, the endopod with a singh^ joint ter- 

 minating in two simihir seta'. These three pairs of ap})en(lages pro- 

 peUed by the powerful muscU^s ah'cady noted make efiicient h)comotor 

 organs, and the nauplii move ra})idly. And even at this early stage 

 some difl'erence can be seen between the nauplii of the ditferent 

 species. Those like C(ili(jtis r((p((.r^ which are \'ery active in the adult 

 form, begin this activity in the early nauplius. while others appear 

 comparatively sluggish . 



Near the posterior end of the body there is a pair of appendages 



