58 NEW SPECIES OF CAIJGUS. 



in the living specimen it could be seen moving slightly, with a 

 sort of contractile motion. In Lepcoptheinis Stromii^ which is the 

 largest of this kind, the siphon-mouth can more readily be seen ; 

 it is shown in Fig. 3 magnified 200 diam., and is seen to consist 

 of a sac surrounded by three muscles, arranged transversely, and 

 having also two longitudinal muscles, by which apparently the 

 process of suction is carried on. This sac is terminated by a 

 very curious mouth, armed with twenty-four curved teeth, arranged 

 in two quarter-circles, and diminishing in size in opposite directions 

 from a point in front. A separate sketch of this mouth, greatly 

 magnified, is given in Fig. 4. Behind the mouth, but connected 

 with the sac above mentioned, is a proboscis, having its inner 

 and anterior extremity shaped like a funnel, and the external end, 

 which projects beyond the mouth, terminated by a sucking-disc or 

 gland, not unlike the extremity of the proboscis of a humble-bee. 

 I have little doubt that this description will also serve in the main 

 for that of the siphon-mouth in the other sub-genera. 



When I became possessed of the living specimens from the 

 Bass, I found that they were themselves encrusted with other and 

 smaller parasites of three different kinds — principally Apoda, and 

 of the species Nephilis — which in one example clustered so thickly 

 upon the Caligus as to conceal its configuration altogether. 



In Figs. I and 2, sketches are given of the underside of the 

 male and female Caligus^ which will be found to differ from each 

 other in some curious and interesting particulars. The body is 

 flat, having its upper surface convex and the under surface 

 concave. On the anterior extremity of the cephalothorax are to 

 be seen two lunules, or sucking-discs, situated close to the edge of 

 the carapace ; they are oval, and for two-thirds of the hinder 

 part of the curve have a double-ridged border more elevated than 

 the front portion — they are apparently not used for walking, as is 

 the case with those of the Arguliis foliaceus. 



There are six pairs of legs attached to the under surface of 

 the carapace. The first pair are small, and terminate with claws 

 or hooks not unlike those of a crab ; the second pair are very 

 large and powerful in the male, but smaller in the female, and are 

 evidently designed for holding the prey firmly. The third and 

 fourth pairs are long, slender, and slightly hooked ; the fifth pair 



