224 BRITISH PARASITIC COPEPODA. 



The above is quoted from Dr. Bassett-Smith's description 

 of this species, as we have not ourselves observed it. 



10. Clavella canthari (Heller). 

 (Plate LXIX, figs. 1-S.) 



1863. (?) Anchorella pagelli Kroyer. (71) p. 295, pi. xvi, fig. 3. 



1865. Anchorella canthari Heller. (58) p. 242, pi. xxiv, fig. 6. 



1877. Anchorella pagelli C. Vogt. (142) p. 432. 



1880. Anchorella canthari Richiardi. (104) p. 152. 



1906. Clavella macrotrachelus Brian. (21) p. 116. 



1910. Lerneomyzon canthari T. R. R. Stebbing. (125) p. 562. 



Female. Small and tolerably robust, but the cephalo- 

 thorax is rather slender and considerably longer than 

 the genital segment, being equal to fully one and a 

 half times the length of that segment ; the proximal 

 end of the cephalothorax bluntly rounded and on each 

 side bearing a small but fairly distinct lobe ; a minute 

 process arising from between the two lobes, and termi- 

 nating in a fascicle of chitinous bristles which penetrates 

 the tissue of the gill filament and then gradually be- 

 comes separated and forms a brush-like appendage. 

 Genital segment moderately stout and subcylindrical, 

 the width equal to rather more than half the length. 

 A small gibbous projection at the proximal end of the 

 segment, as viewed from the side, separated from the 

 segment by a fairly distinct constriction, and forming 

 the base of the cephalothorax. The distal end of the 

 genital segment truncated and obscurely trilobate, but 

 only the middle lobe fairly distinct ; the lateral lobes 

 indistinct and scarcely produced, but the middle one 

 fairly prominent and thickly covered with minute 

 hairs. Egg-strings moderately elongated. Length. 

 The following measurements are taken from a fairly 

 typical specimen : 



Genital segment . . . about 1*8 mm. 



Cephalothorax . . . about 2*5 mm. 



Egg-strings . . . about 3'0 mm. 

 M~le. Small, somewhat similar to the male of C. 

 Brian. 



Habitat. Parasitic on the gill-filaments of the black 



