EGA MONOPHTHALMA. 287 
coalesce dorsally and centrally ; they are reticulated and 
extend obliquely backwards, leaving a small point pro- 
jecting anteriorly between the base of the upper antennz 
and a small central triangular space behind. The inferior 
antenne are separated at the base by a small oblong 
concave plate or labrum. The seven segments of the 
body are nearly equal in size, marked with a faint line 
across the middle ; their sides are furnished with strong 
coxze pointed posteriorly, and with two slight ridges down 
the middle. The first three pairs of legs are directed 
forwards; they are robust, and furnished with strong 
curved claw-like fingers; the four posterior pairs of 
legs are longer and much more slender, with the joints 
nearly equal and spinose, terminated by curved fingers. 
The tail is formed of six segments, of which the five 
first are short and equal, and the terminal one broad, 
oblong, roughish, depressed, with astrong keel down the 
centre ending in a short mucro; the margins of these 
segments are minutely spinose; on each side of the ter- 
minal segment is a pair of foliaceous plates articulated 
to a movable, acutely pointed, somewhat triangular pro- 
cess; the inner plate is wedge-shaped and the outer one 
oblong ; both are densely ciliated round the edge. 
Dr. Johnston, whose detailed description is slightly 
abridged above, adds that this species swims with rapidity 
by the aid of its ‘ caudal fins,” and when it comes in 
contact with a solid body it clasps against it and adheres 
tenaciously. His specimens were taken adhering to large 
cod-fish, of which it is probable they are the “ pedicular 
parasites ;” but, unlike some of their race, they appear to 
be very rare, at least in Berwick Bay, as he could only 
procure three individuals, and the fishermen had never 
observed them before. 
Dr. Johnston also described and figured as a variety of 
