112 BRITISH PARASITIC COPEPODA. 



smaller, and the urosome and caudal rami are not 

 covered. The third and fourth pairs of ventral 

 appendages are also more prominent. 



Habitat. Parasitic on the gills of the bass or 

 sea-perch, Labrox lupus. Plymouth (Bassett- Smith), 

 Barrow Channel, Lancashire (A. Scott), 



Genus 22. HATSCHEKIA Poclt<>, 1902. 



Syn. Clavella Kroyer (1838) and others but not Oken, 1815. 



Body elongated and narrow. Cephalon distinct, 

 small, usually rounded. Thorax short, obscurely 

 biarticulated, without dorsal plates. Genital segment 

 much elongated, narrow, and subcylindrical, five or 

 six times the length of the cephalothorax. Abdo- 

 men and caudal rami very short or obsolete. 



Antennules small and composed usually of not more 

 than six articulations. Antennae short and stout, 

 with strong terminal hooks, sometimes and perhaps 

 generally with a slender spiniform or other appendage 

 at the base of each antenna. Mandibles and maxillae 

 small. First maxillipeds apparently obsolete. Second 

 maxillipeds slender and uncinate. Thoracic legs two 

 pairs, very short, and two-branched. 



Professor van Beneden remarks that this germs is perfectly 

 characterized and easy to distinguish "by the length of the 

 body; by the three pairs of appendages that follow the 

 antennae ; and by the two pairs of short biramose feet. 



1. Hatschekia hippoglossi (Kroyer). 

 (Plate XXXIII, figs. 3, 4 ; Plate XXXIV, figs. 8-11.) 



1838. Clavella hippoglossi Kroyer. (70) p. 196, pi. ii, fig. 3. 



1829-1843. Clavella hippoglossi Guerin. (55) Icon, du Regne Anim., 

 Crustaces, pi. x, fig. 7. 



1840. Clavella hippoglossi M. Edwards. (43) vol. iii, p. 494. 



1851. Clavella hippoglossi P. J. van Beneden. (11) p. 100, pi. iii, 

 figs. 5 & 6. 



1900. Clavella hippoglossi T. Scott. (112) p. 159, pi. vii, figs. 1-6. 



Female. Body slender, elongated, and subcylin- 

 drical. Cephalon small, of an oval form, width greater 



