NON- PARASITIC MARINE COPEPODA. 431 



base ; at the truncate extremity two similar large setae with an 

 intermediate smaller one ; on the middle of the inner margin six 

 sub-equal curved setae of moderate size, and at the extreme 

 angle three of a similar kind but smaller. Abdomen elongated, 

 swollen at the base ; caudal segments rather more than twice as 

 long as broad ; tail setas shorter than the abdomen. Length, 

 iVth of an inch. 



One specimen dredged on a sandy bottom, at a depth of four 

 fathoms, off Seaton Carew, September, 1871. 



The mouth organs of this animal are of very remarkable struc- 

 ture, but I defer attempting any description or giving any draw- 

 ings in the hope of being able to illustrate it completely from 

 a better series of specimens. 



Genus PSEUDOCYCLOPS, nov. gen. 



In general conformation resembling Cyclops. Eight superior 

 antennae of male without a hinge joint, but much swollen in the 

 middle. Inferior antennae two-branched, secondary branch nearly 

 equal in size to the primary. Lower footjaw like that of Cyclops. 

 Swimming feet having both branches three-jointed. Fifth pair 

 of feet in the male very complex in structure, — the external 

 branch of one side produced into a powerful sickle-shaped clasp- 

 ing joint, the whole resembling very closely the male copulative 

 organs of some ostracoda. 



1. Pseudocyclops crassiremis, nov. sp. Plate XVII. , figs. 1-8. 



Left superior antenna of male seventeen-jointed, basal joint 

 large and stout, those next following very short and broad, 

 gradually decreasing in breadth to the fifteenth, which is about 

 as long as broad ; last two joints more slender, about twice as 

 long as broad, the whole limb densely beset on tbe outer margin, 

 especially towards the base, with long setae ; antenna of right 

 side ten-jointed, the central joints much enlarged, last two sud- 

 denly contracted and similar to those of the left side, antepen- 

 ultimate joint armed with a strong lateral subfalciform process. 

 Both branches of inferior antennae bearing numerous long, curved 



