18 
LERNAEOPODA SCYLLICOLA N. SP., A PARASITIC 
COPEPOD OF SGYLLIUM CANICULA . 
By W. HAROLD LEIGH-SHARPE, B.Sc. (Iond.). 
Part II. 
(With 11 Text-figures.) 
{The figures are all drawn from specimens mounted in Farrant's medium.) 
Part I of this paper, which dealt exclusively with the females, appeared in 
Parasitology, vm. 262. After examining some dozens of dogfish each month 
for the previous three years I, at length, on April 2nd 1918 obtained from two 
separate dogfish caught during the preceding week at Plymouth, three 
females of Lernaeopoda scyllicola which were accompanied by males. 
Males, which are rarely collected in the family Lernaeopodidae, are 
unknown hitherto in some species, and for the genus Lernaeopoda have been 
described only very inadequately as to the appendages in L. bidiscalis by 
Kane (1892), and superficially in two other species, viz. L. elongata and L. galei. 
A detailed description of this species therefore supplies a pressing want. 
Sexual dimorphism attains striking proportions in this family, the males 
showing a marked dissimilarity in size, structure of the body, and its 
appendages, as also in the methods of prehension and locomotion. For, as 
has been said, though the free-swimming period of the male larva is no longer 
than that of the female, and the two often fasten themselves side by side 
upon the same host fish, whereas the attachment in the case of the female is 
permanent throughout life, it is but temporary in the male. When each partner 
has arrived at sexual maturity, the male, which is fixed only by the frontal 
filament, describes, with the point of attachment as centre, an arc until, on 
coming in contact with the body of the female, he abandons the filament and 
fastens himself to the female by the second maxillae and maxillipedes, re¬ 
maining there for the remainder of his life. Not being permanently attached 
he is able to crawl about over the female’s body, but such motion is slow and 
laborious, and probably performed only when necessary. He does not increase 
his size at each successive moult like the female, but remains dwarfed showing 
less degeneration, and more distinct segmentation in the trunk region. 
A curious similarity in position is exhibited by each of the attached males. 
Each was located on the left side of the female, immediately behind the 
cephalothorax. I have previously remarked and figured that the female 
