PARASITIC COPEPODS—CALIGID.E— WILSON. 



503 



edge is crenated and fringed with long cilia (tig. (J, a). This flap is 

 flexible and capal)le of more motion than the remainder of the lip, but 

 to call the latter "'immovable'' (Pickering and Dana) is certainly mis- 

 leading. The whole mouth tube moves together and freely, and cer- 

 ttiinly the dorsal portion of it is as movable as the ventral. In Caligns 

 vdpa.i' the anterior portion of the chitinou.s margin, instead of being- 

 concave, is convex like the lower lip, and projecting in front of it is 

 a narrow flexible meml)rane flap, with its front edge incised at the cen- 

 ter and fringed throughout with cilia (flg. 10). 



The statement of Pickering and Dana that the mouth "appears to 

 be composed of the upper and lower lips, luiited with the diflferent 

 parts of a pair of maxilUv '' (183^s, 

 p. 73) can not stand. Those au- 

 thors made no attempt at an}" 

 explanation of the position or 

 connection of the maxilla^ re- 

 ferred to, except to state that 

 they corresponded to the first 

 pair of maxillse in decapod Crusta- 

 cea. And even this was not stated 

 directly, but in a roundabout fash- 

 ion, for they found a single pair 

 of appendages which they said 

 corresponded to the second max- 

 illa3 in decapod Crustacea, but 

 which they called the first maxil- 

 lipeds. They proved to be in 

 reality the second antennie; it 

 must have been, therefore, the 

 first maxillie which they thought 

 were combined with the upper 

 and lower lips. But we have al- 

 ready seen that both pairs of 

 maxillfe are fully accounted for 

 outside the buccal tu))e. And A. Scott has shown ))y the innervation 

 in Lcpeopldhi'ti'iis. jxrtoral/.s that the claws which Pickering and Dana 

 considered as appendages of their " first maxillipeds" are really the 

 first maxilke. 



Of the two pairs of maxillipeds, the first are situated about halfway 

 between the apex of the mouth and the lateral margin of the carapace. 

 Each one of this pair is two-jointed, the basal joint moderately stout 

 while the longer terminal joint is ver}" slender and terminates in two 

 or three short and stout spines. Their function is probably that of 

 keeping the mouth clean of foreign matter ))v a sort of coni))ing 

 motion (tig. 11). 



The second maxillipeds arise near the mid line, a little posterior to 



Fin. 10.— 'DORSAI, SURFACE OF THE MOUTH TUBE 

 OF CaLIGUS KAPAX in an ADVANCED CHAUMUS 

 STAGE, r', ROD ON LATERAL MARGIN OF FRAME- 

 WORK OF UPPER LIP. 



