[fraser] COPEPODS PARASITIC ON FISH 55 



(Jiospitalis, on account of the species being host to so many 

 parasites.) 



Found in large numbers in company with L. parvicruris on the 

 flounder, Platichthys stellatus. Some specimens were also obtained on 

 Pleuronichthys cœnosus and Gadus macrocephalus. 



Lepeophtheirus nanaimoensis, Wilson 

 Pl. IV, Figs. 59-61. 



Lepeophtheirus nanaimoensis. Wilson, Contr. to Can. Biol., 



1912, p. 89. 



Male: Body short and broad, about three-fifths of the size of the 

 female. Carapace nearly as wide as long, frontal margin slightly 

 curved, but slightly incised; posterior sinuses deeper than wide; 

 median lobe four-ninths the width of the carapace ; lateral lobes reach- 

 ing nearly as far back as the median lobe. Free segment almost the 

 same width as the genital segment, narrowed anteriorly. Genital 

 segment two-sevenths the width of the carapace; separation into two 

 segments plainly indicated on the ventral surface, each segment with 

 a pair of legs, plainly visible from the dorsal as well as from the ventral 

 surface. The fifth pair forms the postero-lateral angles., each with 

 four setae nearly equal in length, the exterior the shortest. Each of 

 the sixth pair is provided with two setae, the inner one being much the 

 longer. Abdominal segment slightly wider than long. Anal laminae 

 as long as broad, each with four setae projecting posteriorly and a 

 much smaller placed ventrally and projecting laterally. Of the pos- 

 terior setae, the second from the inside is the longest, the third being 

 slightly longer than the first and the fourth the shortest. The append- 

 ages, with the exception of the second antennae, are not very different 

 from those of the female. The second antennae are strongly developed; 

 the basal joints are corrugated and the basal part of the claw is cor- 

 rugated also; the claw is divided into two, near the tip and is provided 

 with a spine a short distance proximal to where the division takes 

 place. 



Total length 2-4 mm., length of carapace 1-55, width 1-4, length 

 of genital segment 0-45, width 0-4. 



The female of this species was described by Wilson but he ob- 

 tained no females. The only specimens obtained, male and female, 

 were from a flounder of which the species was not determined, caught 

 in Winter harbour, off Quatsino sound. 



