216 BRITISH PARASITIC COPETODA. 



2. Clavella rugosa (Kroyer). 

 (Plate LXV, figs. 4, 5 ; Plate LXVI, figs. 1-7.) 



1837. Anchorella rugosa Kvoyer. .(70) pi. 1. vol. i. p. 294. pi. iii. fig 1 . t>. 



1850. Anchorella rugosa Baird. (4) p. 338, pi. xxxv, fig. 8. 



1851. Anchorella rugosa P. J. van Beneden. (11) p. 114. pi. vi, fiu\ 7. 

 1900. Anchorella rugosa T. Scott, (112) p. 176, pi. viii, figs. 45-48. 



. Cephalothorax tolerably elongated and 

 vermiform, about one and a half times longer than the 

 genital segment; usually more or less recurved mid 

 reaching considerably beyond the distal end of the 

 segment. Genital segment stout, rugose, quadriform, 

 and somewhat flattened, length and width about equal. 

 Abdomen obsolete or nearly so. 



Antennules composed of three joints, the first 

 moderately large and stout, the other two smaller 

 but the end joint rather longer than the preceding one ; 

 antennae stout and somewhat similar in structure to 

 those of Brachiella. Mandibles small, slender, and 

 coarsely dentate near the distal end of the inner 

 margin. Maxillae furnished with three moderately 

 stout terminal spines, and two smaller ones on a some- 

 what rudimentary subterminal lobe. First maxillipeds 

 short, stout, and strongly uncinate. Second maxilli- 

 peds rudimentary, being reduced to a small button-like 

 projection at the anterior end of the genital segment, 

 which is fixed to a horn-coloured chitinous plug that 

 penetrates the tissues of the fish. Egg-strings toler- 

 ably stout and elongated, more than twice the length 

 of the genital segment, and containing numerous ova. 

 Length exclusive of the cephalothorax about 4 mm., 

 but the size is slightly variable. 



Male. The male is very small and short, the height 

 being equal to fully one and a half times the length ; 

 the general outline, seen from the side, is subconical. 

 Both pairs of maxillipeds, though short, are furnished 

 with stout terminal claws. 



Habitat. Parasitic on the gills and gill-covers of 

 cat-fishes (Anarrhichas lupus). On cat-fishes captured 



