674 A NKW KNDOPARASITIC COPEPOD, 



Irom tliat in the possession of a paired ovary, the absence of a 

 chitin-lined "end-gut," and great reduction of the nervous system. 

 Type, U. hilli Kesteven. 



Ubius hilli, sp. nov. 



Evternal Features. — Form cylindrical, more or less abruptly 

 truncated anteriorly, and tapering to a point; bifid in the male, 

 posteriorly (Fig. 4). The size is variable; following are the aver- 

 ages of six measurements: female ().4 x 0.8; male 2.6 x 0.4 mm. 

 If the diameter be taken as the unit of measurement, then, with 

 fair constancy, the length of the female is eight, and that of the 

 male six. In living specimens, the length was probably greater and 

 the diameter less, since longitudinal body-muscles are alone well 

 developed, and must have contracted when the animals were killed. 



Colour opaque white. 



Cuticle thin, very flexible, and showing very fine, closely set, 

 annular hair-like thickenings. 



External apertures: the mouth (Fig. 2) is situated ventrally, 

 almost at the extreme anterior end. Anus absent. The vulvae are 

 situated ventrally on either side of tlie mid-line, well towards the 

 posterior end; each is surrounded by three laterally compressed 

 jointless appendages, two on either side of, and one directly behind 

 the orifice (Fig. 3). 



The appendages (Fig. 2) number five pairs; two are situated 

 immediately in front of the mouth, the remainder equidistant 

 behind it; the fifth pair being situated almost at the junction of 

 the anterior and middle thirds of the length of the body. 



The antennules (Fig. 5) are short and flattened, composed of a 

 single segment, and provided with a toothed cutting inner edge. 

 The musculature is composed of two bands of striated muscle, 

 wliich arise from an endoskeletal cuticular rod above, and are 

 inserted well towards the distal extremity of the appendage. 



The antennae (Fig. 6) are three-jointed chelae, the first segment 

 short and broad. The arrangement of the musculature is shown in 

 Fig. 2. The third pair, mandibles (Fig. 7), are two-jointed, the 

 first joint short and stout, the second flattened, of triangular out- 

 line, but with the apex notched; the musculature of these is also 



