Thomson. — On Parasitic Copepoda. 355 



The oviferous tubes are broken off in my specimens, so 

 that I cannot estimate their length. 



The first antennce are very small and 2-jointed ; the termi- 

 nal joint consisting of a slender tapering seta, while the basal 

 one broadens out to its junction with the frontal lamella, witli 

 the incurved margin of which it appears to be anchylosed. 

 The antennce of the second pair are in the form of strong claws, 

 2-jointed, and with the joints somewhat flattened. The 

 mouth sucker is stout and rather distinctly segmented in the 

 middle. At its sides stand a pair of bifurcate teeth, which 

 are strong, chitinous, and dark-l)rown in colour ; from their 

 position these are probably modified maxillary palps. The 

 first foot-jaics are long and slender, the second joint tapering 

 to a long weak extremity, and bearing a slender seta. The 

 second foot-jaws are strong and 2-jointed. The sternal fork is 

 bifurcate ; the upper branch on each side rather short and 

 rounded ; the lower again shortly 2-branched at its ex- 

 tremity. 



The legs of the first pair are 1-branched ; branch 2-jointed 

 (unless the basal joint, which appears to be anchylosed to the 

 sternum, be considered to be a third). The terminal joint 

 bears three plumose setaa on its outer margin, and at its ex- 

 tremity a long nearly-straight spine and two 3-pronged spines. 

 These latter are very peculiar and anomalous organs, and 

 quite unlike any appendages I have seen in other animals of 

 this class. I have accordingly given figures of them con- 

 siderably magnified (Plate XXVIII. , fig. 10, b). 



The legs of the second pair are 2-branched. Outer branch 

 2-jointed and in a continuous line with the basal joint, 

 stretching transversely across the body of the animal ; its 

 terminal joint bears 4 strong chitinous spines directed out- 

 w^ards, 1 short (plumose) seta at its extremity, and 3 short 

 and 1 long setae directed inwards. (All the setae on the legs of 

 these animals — unless otherwise specified — are beautifully 

 plumose.) The inner branch is 3-jointed, and stands at right- 

 angles to the outer : its first joint bears a seta on the inner 

 margin; the second has 2 sette, also on the inner margin, and 

 has the outer margin a little dilated ; the last joint bears 6 

 setae, which diminish in length from within outwards. 



The legs of the third pair are 2-branched, somewhat similar 

 to the preceding pair, but having very large and wide basal 

 plates. Outer branch with 2 powerful hooked chitinous spines 

 on the first joint, and 3 small spines and o setae on the second 

 joint. Inner branch with the first joint simple, rounded, and 

 fringed on the margin ; second joint widely dilated on the 

 outer margin, and with a long seta on the extremity of the 

 inner margin ; last joint very small, rounded, and with 3 short 

 setic. 



