new Parasitic Copepods on Fish. 369 



Female. — Head of large size, longer than broad, largest at 

 the base, which is slightly rounded ; it is strongly arched 

 dorsally from side to side, the margin folding inwards on the 

 under surface ; in front the border is convex and prominent, 

 showing no median notch, from the underside of which 

 frontal border the six-jointed setiferous anterior antennas are 

 seen. 



Thorax seen from the dorsal surface divided into three 

 segments, each having a median indentation posteriorly; 

 they are broader than the head and are together somewhat 

 longer : the anterior segment is but indifferently marked off; 

 this is the true second thoracic segment bearing the second 

 pair of thoracic limbs, the first being united with the cephalic 

 portion ; it is less wide than the following segments and very 

 short : the second free segment is much broader than long, 

 with rounded sides, from under which can be seen projecting 

 the third pair of limbs ; the third free thoracic ring is slightly 

 smaller than the last, but of similar shape, being not so long 

 as broad and deeply cut away posteriorly ; the sides of 

 these segments are deeply pigmented, and the alimentary 

 canal is easily visible down the centre ; the usual posterior 

 tunic or plate common to the whole genus appears to be, 

 however, entirely absent, the abdomen being quite bare, 

 projecting between the two greatly elongated processes repre- 

 senting the fourth pair of limbs; on either side of it from the 

 posterior edge of the lobe of the last segment, is seen a small 

 rounded flap or plate partially covering the base of the fourth 

 pair of limbs ; these may be the rudiments of the dorsal tunic. 

 The abdomen is rather longer than the last thoracic seg- 

 ment ; it is composed of three distinct portions, the second 

 partially overlapping the third : the first is of a rounded 

 shape, but broader than long ; the second is pointed at the 

 extremity, it is constricted in the middle, dividing it into two 

 parts ; to the upper and wider are attached the ovarian tubes, 

 to the narrower the two stalked dark spermatophores. The 

 third abdominal joint is oblong in shape, traversed by the 

 intestinal tube ; the anal opening is seen at the end between 

 the two caudal plates, which are oval in shape, somewhat 

 divergent, and placed on the under border. 



From the ventral side one sees the six-jointed setiferous 

 anterior antenncc, and placed far forward the triarticulate 

 posterior antennas; the first two joints of the latter are very 

 broad and muscular, the last in the form of a curved hook : 

 beneath these on the median line is found the mouth, of a 

 pointed conical shape ; on each side of this near the base a 

 slender triarticulate and a thicker biarticulate process can bo 



