168 BRITISH PARASITIC COPEPODA. 



at the proximal end, but tapering to the more or less 

 attenuated distal extremity ; both margins fringed 

 with minute prickles or teeth. First maxillipeds 

 small and provided with a straight terminal spine 

 which is sometimes serrated. Thoracic limbs two pairs, 

 biramose; rami rudimentary. Caudal rami obsolete. 



Male. Very small. Cephalothorax considerably 

 dilated. Abdomen small, more or less segmented. 

 Maxillipeds fairly well developed, and fitted for 

 grasping; other appendages somewhat rudimentary. 



1. Chondracanthus cornutus (0. F. Miiller). 



(Plate XL VII, figs. 1,2; Plate LII, fig. 5 ; Plate LIII, 



figs. 1-9.) 



1777. Lernxa comuta O. F. Miiller. (85) p. 124, pi. xxxiii, fig. 1. 



1815. Anops cornuta Oken. (91) t. iii. 



1816. Entomoda cornuta Lamarck. (72) vol. iii, p. 233. 

 1822. Lernentoma cornuta Blainville. (24) p. 441. 



1832. Chondracanthus cornutus Nordinann. (89) p. 111. pi. ix, figs. 

 5-10. 



1850. Lernentoma cornuta Baird. (4) p. 328, pi. xxxv, fig. 2. 



1851. Chondracanthus cornutus P. J. van Beneden. (11) p. 108, pi. iv. 

 figs. 1-4. 



1863. Chondracanthus cornufus Kroyer. (71) p. 249, pi. xiii, figs. 7 a-8. 



1877. Chondracanthus cormdus C. Vogt. (142) p. 78, pi. vi, figs. 4-8. 



1900. Chondracanthus cornutus T. Scott. (112) p. 164, pi. vii, figs. 19- 

 31. 



1906. Chondracanthus cornutus Norman & T. Scott. (88) p. 217. 



Female. Head ovate, somewhat longer than broad ; 

 thorax narrower ; genital segment rather wider than 

 the head, moderately elongated, flattened, and usually 

 with a constriction sometimes indistinct dividing it 

 into two subequal portions ; the postero-lateral corners 

 of the segment produced backwards into straight and 

 narrow prolongations, their length being rather less 

 than the width of the segment. Abdomen very small, 

 bisegmented and rather shorter than the lateral pro- 

 longations of the genital segment. 



Antennules robust and tolerably large but showing 

 scarcely any structure. Antennae short and armed 

 with strong terminal hooks. Mandibles stout, falci- 

 form, attenuated towards the distal extremity, and 



