NO. 1368. 



DESCRIPTION.^ OF xiRd ULIDA-^WILSON. 



649 



a 



Fig. 29. — Scale.s ox ventral .surface ftp 



THE POSTERIOR MAXII.I.IPEDS OF ARun.rs 

 VERSICOLOR. 



or 15 degrees to the body and is an elongated ellipse in outline (.see a in 

 fig. 29). Its ))asal half, whicli is fused with the sunnnit of the i)apina. 

 is solid, but the free half is cut into from two to six long and acumi- 

 nate teeth. In general the scales nearer the anterior margin of tlic 

 maxilliped have the larger luimber of 

 teeth. Often one of the outer teeth is 

 short and stands out at an angle from 

 the others like a thumb. Evidently 

 such an arrangement forms a surface 

 which nuist give the copepod a firm 

 hold even through the slimy coat of 

 the fish's body. 



The terminal joint of the.se maxilli- 

 peds ends in three hooks of unequal 

 size; the anterior one is much the 

 largest, with a thick, blunt tip armed 

 with a single short, sharp seta. The 

 other two are more slender and strongh- curved (tig. 3(»). 



Swlmin'nig ZtY/*-.— The.se are long and slender and reach far In-yoiid 



the edge of the carapace. The}' are 

 fringed with stout plumose setae and 

 enable this argulus to swim with great 

 power and rapidity. The tlagella upon 

 the first two pairs have a double curve, 

 as can be seen in fig. 81, which is a 

 dorsal xiew looking through the cara- 

 pace in a bleached specimen. The 

 l)a.sal lobes upon the- posterior legs are 

 ver}' long and their tips extend beyond 

 the edge of the abdomen. Thej^ have the usual boot shape, with a 

 single seta on the toe of the boot much longer than the rest. The 

 chitin rings in the lateral 

 lobes of the carapace 

 extend farther forward 

 than those in americanuH^ 

 and the concavity in 

 the posterior one into 

 which the smaller ring 

 fits is on the inner mar- 

 gin a short distance back 

 from the anterior end in- 

 stead of at the end itself. 



Tactile papilhi'.^TheHii are long and slender in the female and curve 

 in toward each other at the tips, while in the male they are so rudi- 

 mentary as to be almo.st invisil)le. 



Clrcidation.—T\\m is the same as that given for A. f.Jni,; us. 



Fig. 30. — Terminal joint of posterior 



MAXILLIPED of ARGULrs VER.SICOLOR. 



Fio. 31. —Dorsal surface of the anterior leg on the right 



SIDE OF ARGULUS VEPSICOLOR. SHOWING SIZE AND ATTACHMENT 

 of normal FLAC.ELLUM. 



