138 BRITISH PARASITIC COPEPODA. 



be slender and flexuose, or in the form of spines. 

 Antennae and mouth-organs more or less rudimentary. 



Male. Body slender, distinctly segmented, and 

 furnished with several cephalothoracic appendages, 

 including antennules and antennae; first and second 

 maxillipeds and two pairs of thoracic legs all bira- 

 mose ; the first abdominal segment also sometimes 

 provided with a pair of limbs. The first maxillipeds 

 with strong terminal hooks forming powerful grasping 

 organs. Abdomen usually composed of about eight 

 segments. 



Habitat. The species belonging to this Family 

 occur free in the mucus canals and sinuses of various 

 fishes. 



Genus PHILICHTHYS Steenstrup, 1861. 



Female. Head small, rounded. Body elongated 

 and distinctly segmented ; no dorsal plates, but the 

 body, including the head, furnished with a number of 

 lateral and ventral processes, moderately slender, and 

 more or less curved inwards upon the ventral aspect. 

 The egg-strings, which are of moderate length and 

 thickness, extending alongside the body, and are partly 

 enclosed and supported by the curved lateral and 

 ventral processes. 



There is in the female a single median eye-spot. 



Male. The male is much smaller than the female. 

 The body is slender and distinctly segmented. The 

 anterior part of the body consists of three segments, 

 the first moderately large and bluntly rounded in front, 

 the other smaller. The posterior portion is also 

 segmented, very narrow, and considerably longer than 

 the front part. 



Antennules slender, composed of six articulations ; 

 antennae two-jointed and provided with two hook-like 

 setae. The first maxillipeds moderately large, the 

 second feeble. 



Only one species is known. 



