SEA-FISHEEIES LABOEATOEY. 151 



from sponges collected by Dr. Hanitsch at Port Erin, 

 Isle of Man, in August, 1894. This species is very like 

 Cletodes lata in general appearance but is easily dis- 

 tinguished from it on dissection by the structure of the 

 antennules, the proportional lengths and armature of 

 the outer and inner branches of the first pair of swimming 

 feet, and also by the form of the fifth pair of feet. 



Nannopus palustris, Brady. 



Several specimens of this species were obtained in the 

 mud collected from the Mussel beds near Duddon and 

 from mud sent to the laboratory from the Fleetwood 

 Oyster beds. It seems to be a brackish water species and 

 in general appearance is very like PlatycheUpus litt oralis 

 another brackish water copepod, it can be distinguished 

 from that species however, even without dissecting, by 

 making an examination of the fifth pair of feet and also 

 of the inner branches of the third and fourth pairs of feet. 

 Nannopus palustris has two ovisacs and PlatycheUpus 

 littoralis one only. 



Idya elongata, n. sp. PI. IV., figs. 21—24; PL V., 

 figs. 1 — 5. 



Description of the species. — Female. Length ■ 74 millim. 

 ( :; \-th of an inch). Body seen from above elongate narrow, 

 tapering rapidly towards the posterior end, the length 

 being nearly equal to four times the greatest breadth ; 

 rostrum prominent with a bluntly rounded apex. Anten- 

 nules short and comparatively stout ; shorter than the 

 cephalothoracic segment, eight-jointed ; second and third 

 joints longer than any of the others, as shown in the 

 following formula : — 



11 . 16 . 17 . 13 . 6 . 8 . 5 . 12 

 1 2 3 45678 



Antenna?, mandibles and maxillae nearly as in Idya 

 gracilis, T. Scott. Foot-jaws also similar to those of that 



