190 BRITISH PARASITIC COPEPODA. 



rounded knobs. Two moderately long and slender 

 appendages spring from the ventral aspect just in 

 front of the base of the egg-strings and extend back- 

 wards some distance beyond the end of the genital 

 segment. Abdomen and caudal rami obsolete. Anten- 

 nules stout, short, and apparently three-jointed; 

 antennas short with a gibbous basal part, and the 

 small end joint provided with a minute terminal cla\v. 

 Mandibles slender, moderately elongated, and with a 

 portion of the inner margin of the end joint coarsely 

 serrate ; maxillae simple and furnished with a few 

 apical setae. No thoracic legs observed. Length 

 from the apex of the second maxillipeds to the end of 

 the posterior appendages about 47 mm. Colour 

 opaque white tinged with red. 



Male. Very small, scarcely reaching beyond two 

 millimetres in length. Somewhat like Lern&opoda 

 didhdd in general appearance but larger. Thorax and 

 abdomen segmented. Maxillipeds short and stout and 

 furnished with strong terminal claws. 



Habitat. Parasitic in the nasal fossae or spiracles of 

 gray (or blue) skates (Raia balix). Firth of Forth; 

 frequent on large Raia batis brought to the Fish- 

 Market at Aberdeen (T. Scott). Firth of Forth, 1862 

 (Dr. Wilson). Polperro, Cornwall (A. M. Norman). 

 Irish Sea (A. Scott). Usually only one specimen is 

 present in a spiracle, but two and sometimes three 

 have been observed almost blocking up the spiracle. 



2. Charopinus dubius T. Scott. 

 (Plate LV, fig. 5.) 



1900. Charopinus dubius T. Scott. (112) p. 130, pi. vii, fig. 15. 



Female. Somewhat resembling Charopinus dalmanni 

 Retzius in general appearance and also in some of its 

 appendages, but considerably smaller, being little more 

 than half the size. 



The principal structural characters by wnich it is 

 distinguished from that species are those of the 



