of the Fishery Board for Scotland. 



151 



Lepeophtheirus nordmanni (M.-Edwards). (PI. V., figs. 32-37.) 



1840. Caligus nordmannii, M. Edw., Hist. Nat. Crust., vol. iii., 

 p. 455, No. 10. 



1850. Lepeophtheirus nordmannii, Baird, Brit. En torn., p. 275, 

 PI. XXXII., fig. 10. 



This is a moderately large species; the specimen represented by the 

 figure measures about half-an-inch in length (12 mm.). The cephalic 

 shield is of an oval form and is distinctly larger than the last segment 

 of the thorax. The abdomen is short (fig. 32). 



The mandibles in this species are long and slender, but the last joint 

 is comparatively short, and has a short serrated margin (fig. 34). The 

 branches of the sternal fork are long and somewhat slender ; they are 

 also to some extent divergent (fig. 35). The posterior foot-jaws are large 

 and armed with long terminal claws. 



The branches of the fourth pair of the thoracic feet are three-jointed, 

 and are provided with five seta3 s three of which spring from the apex of 

 the last joint, and one from the outer distal angle of the first and second 

 joints (fig. 37). The fifth pair, which have a sub-triangular outline, are 

 broadly foliaceous. 



Habitat. — On a short sun-fish, Orthagoriscus mola, landed at Aberdeen 

 Fish Market on 1st September 1899. One specimen only was obtained. 



Remarks. — The abdomen of this specimen of Lepeophtheirus 

 nordmanni obtained by me appeared to be rather more elongated than 

 that which is represented in Dr. Baird's figure. He also describes the 

 branches of the sternal fork as ; ' sharp-pointed," but in our specimen the 

 branches, though slender, are somewhat blunt at the ends. 



Lepeoplitlieirus hippoglossi (Kroyer). (PI. V., figs. 38-42 ; PI. VI., 

 figs. 1-2.) 



1838. Caligus hipjpoglossi, Kroyer, Naturli. Tidsskrift, R. i., 



vol i., p. 625, PL VI., fig. 3. 

 1850. Lepeophtheirus hippoglossi, Baird, Brit. Entom., p. 276, 

 PI. XXXII., figs. 1-2. 



The ovigerous female represented by the drawing (PI. V., fig. 38) 

 was rather more than half-an-inch in length (about 13*5 mm.). The 

 cepalic shield was large and of an oval outline, but the last segment of 

 the thorax was comparatively small and narrow, and rather longer than 

 broad. The abdomen was small, and slightly constricted near the 

 posterior end. The caudal segments were very short. 



In this species the mandibles are long and slender, though scarcely so 

 much so as those of Lepeophtheirus nordmanni. The sternal fork differs 

 from that of any of the other Lepeophtheirus recorded here in having 

 each of the two branches distinctly biped (fig. 2, PI. VI.). The fourth 

 pair of thoracic feet have the branches three-jointed and furnished with 

 four setae, three at the apex and one on the outer distal angle of the 

 second joint (fig. 41, PI. V.). The fifth pair consists of small triangular 

 plates situated behind the bases of the ovisacs. 



In the adult male (fig. 39, PI. V.) the last thoracic segment is very 

 small, and the fifth pair of feet are more or less exposed. The male is 

 also much smaller than the female, being scarcely half as long. In the 

 male the antennse appear to be also somewhat different from those of the 

 female, the basal joint is more dilated and the terminal claw is more 

 strongly hooked. 



Habitat. — Taken on the backs of large halibut, Hippoglossus vulgaris, 

 landed at Aberdeen Fish Market during the summer and autumn of 

 1899. 



