SOME PAfiASlTiC COPEPODA. 53 



curved backwards, are borne near the base of this structure. Between the second antenna?, 

 and making an angle of 45° with them, is the long mouth-tube, which hangs downwards. 

 The upper and lower lips can be readily separated and the mandible is seen lying 

 between them. Posterior to the mandibles at the base of the mouth-tube are the first 

 pair of rnaxillse. The second maxilla? are situated far behind the first pair, about half- 

 way between the extremity of the head and the bend of the neck. Their ends 

 are directed forwards and project considerably beyond the surface of the head. A 

 constriction can be seen at the back of the head and another where the body is bent 

 back ; on this segment the arms are borne. Posterior to the bend is a narrow short 

 portion passing gradually into the wide genital segment. Indistinct traces of four 

 segments can be made out in this portion of the hody. The first two subequal ; the 

 next about one and one-third longer, the fourth about three times as long as the first. 

 It is doubtful if these are true segments. Two bands of muscle can be seen running down 

 the centre of the genital segment ; at a point which corresponds with the first constriction 

 behind the neck their continuation seems interrupted : this is probably a true segment. 

 These muscles run backwards almost to the base of the abdomen. On each side of them 

 are two large masses of ova extending forwards into the first segment. There is another 

 mass of ova beneath the ventral surface, and lying between these masses are a pair of 

 thick-walled cement-glands (PL 9. fig. 16, CO.), which extend forward to a point about 

 the middle of the total length of the genital segment. Prom the side they can be seen 

 curving round in the prominences at the posterior margin of the body just above the 

 geDital openings (fig. 16, O.O.). 



Appendages (female). 



First Antennce (PI. 10. fig. 23). — Two-jointed, basal joint one and a half times as long 

 as the terminal joint, which is slender, bearing two delicate tapering setae, one of whicb is 

 thicker than the other, and two more very small seta?. Bather below the middle of this 

 joint is another small seta. 



Second Antennce (PI. 10. fig. 19). — Stout, biramous. The two branches are borne on a 

 stout basal portion which is not distinctly segmented. The outer branch is about the 

 same thickness throughout, with a blunt truncated extremity. This portion bears 

 three rounded knobs, the two outer smaller and more raised than the median knob. 

 All are covered with fine bristles and a few small hooks. The outer margin of this 

 branch is also covered with bristles. The inner branch of the main stem is not so 

 stout as the outer branch. The outer edge is covered with bristles, and above this 

 part is a rounded knob on which is a slightly hollow disc full of bristles with a small 

 seta at its base and another longer seta near the outer edge. On the inner side of this 

 disc is a strong sharp claw with a small seta at its base. The segmentation of both 

 branches is indistinct. 



Mandibles (PL 10. fig. 20). — Four large teeth alternating with three small teeth : 

 these seven are followed by four more, the first two of which are longer than the other 

 two. Behind the teeth is a cutting-edge. 



First MaxilliB (PL 10. fig. 21). — Biramous. The outer branch bearing three long 

 tapering seta?. The inner branch small and stump-like, bearing two small setas. The 



SECOND SERIES. — ZOOLOGY, VOL. XI. 8 



