172 BRITISH PARASITIC COPEPODA. 



and not so clearly defined as in C ho udr acanthus solese, 

 and together scarcely equal to a third of the entire 

 length of the animal. Genital segment robust, some- 

 what flattened, and about twice as wide as the thorax ; 

 a distinct transverse constriction dividing it into two 

 subequal portions ; the general outline of the segment 

 broadly oval, its extreme length being about one 

 and a half times greater than the width ; the postero- 

 lateral corners of the distal portion produced into 

 moderately short, narrow, arcuate, and slightly con- 

 vergent lobes, enclosing between them the small 

 biarticulated abdomen. 



Antennules moderately robust and indistinctly bi- 

 articulated, with one or two subapical setae. Antennas 

 short, and armed with small but stout terminal claws. 

 Mandibles and other mouth-appendages somewhat 

 similar to those of Ghondr acanthus cornntu*. Thoracic 

 legs rather small and rudimentary. Length about 

 5 mm. Egg-strings about the same length. 



Male. Very small, and somewhat similar in size 

 and structure to the male of Chondracanthus cornutus. 



Habitat. Parasitic on the gills and inside the gill- 

 covers of long rough dabs (Drepanopsetta platessoides 

 Fabr. = Platessa liuuiudoides (Bl.)). Firth of Clyde 

 (T. Scott}. Irish Sea (A. Scoff). 



This species of Chondraatnthus lias not been observed on 

 any other kind of fish. It was also from long 1 rough dabs 

 that Kroyer obtained his specimens of this parasite. 



5. Chondracanthus depressus T. Scott. 

 (Plate XLI, figs. 2-4 ; Plate LVI, figs. 1-7.) 



1905. Chondracanthus depressus T. Scott. (116) p. 114, pi. vi, figs. 7-13. 



Female. Head subquadrangular, nearly as long 

 as broad. The first and second thoracic segments 

 subequal, very short, and somewhat narrower than 

 the cephalic segment, and that segment combined with 

 the thorax not more than about a third of the entire 

 length of the animal, the other two-thirds comprising 



