1206 



CRUSTACEA. 



The organs of the mouth were not completely made out. The man- 

 dible has an acutely lobed summit. In one of the pairs of maxillae, 

 the last joint has the inner apex prolonged inward claw-like and cor- 

 neous. Beneath this acute apical prolongation there are two or more 

 slender processes, one having one margin and the apex short setose, 

 and the other with very minute setae at apex, and somewhat brush- 

 like. In the other pair of maxillae, there is a large oblong lamellar 

 joint, fringed at summit, having a small rounded process or lobe on 

 the inner side. (Figs. 12 a to d, PI. 85.) 



The maxillipeds are, properly, as they have been called in treating 

 of the Calanidae, the anterior feet There are three joints; the second 

 oblong, with one or two short setae towards the apex; the third a 

 slender claw or ringer, which folds against the preceding. 



There are four pairs of natatories, and rarely a fifth of similar cha- 

 racter. These natatories, wherever particularly examined, consisted 

 of three joints to each branch, and the shorter branch was not more 

 than half the length of the other; in the fourth pair, the length is not 

 over one-third the longer branch, and in some species it is much 

 shorter. In the longer branch there are two flattened spines on the 

 outer margin of the third joint, besides an apical, and one apical to 

 the other joints. The last joint terminates in an ensiform seta, 

 ciliated only on the inner side. (Figs. 4 g, 4 h, PL 85.) 



The abdomen is one- to three-jointed. It is oblong, and usually 

 about half as long as the cephalothorax. The basal half is rather 

 broad and suboval; and within, two vessels may be often seen corre- 

 sponding to the extremities of the two ovaries. The remaining part 

 is quite slender. There are no appendages below to the basal por- 

 tion of the abdomen, or only minute obsolescent appendages, or setae. 



In some species there were two oblong oval or falciform appendages 

 to the upper part of the abdomen, near its hinder extremity, which 

 appeared to be the remains of the ovaries after the exclusion of the 

 eggs (fig. 6 a, PI. 86). Yet occasionally these appendages were in a 

 cluster. They were half as long as the abdomen, or even longer. 



The caudal stylets are slender styliform, and are either quite short, 

 or longer than the abdomen. They have three or four setae, and the 

 inner of the three is usually largest; they are never very long. 



Two ovaries were distinct in some species. But external ovaries 

 were not met with in any of the many specimens examined. These 



