00 BRITISH COPEPODA. 
shorter, setz, the longer one being geniculated in the 
middle, and bearing on the distal half a pectinately 
arranged series of minute cilia; the outer branch has 
all its jomts armed with strong apical spines, between 
which the external margins are closely ciliated. The 
second and third pairs of feet have both branches 3- 
jointed, the inner branches shorter than the outer (fig. 
10); inner branch of the fourth foot (fig. 11) short, 
2-jointed; basal joint of the fifth pair (fig..15) broad, 
the inner segment scarcely at all elongated, but bearing 
five, stout, shortly-plumose setz; second joint ovate, 
narrow, provided with one long apical and three mar- 
ginal sete, all of which are plumose, the inner margin 
has also two much shorter sete. ‘Tail-segments (fig. 
17) not much longer than broad, bearing two apical 
setz, the innermost of which is at least three times 
longer than the outer, and is minutely aculeate along 
the margins; anal operculum (fig. 17 a) denticulated. 
Length ;gnd of an inch (1‘1 mm.). 
Male.—Anterior antenna (fig. 3) constricted so as 
to form a hinge between the fifth and sixth joints; 
thickly beset with short marginal hairs. The second 
and third joints of the inner branch of the second foot 
are incompletely separated (fig. 12), and the apical 
setze are much reduced in size; in the third foot the 
inner margin of the second joint is produced into a 
long, downward-pointing, spinous process (fig. 13), 
while the third joint has only a single small apical seta, 
all the other setze of the branch being wanting; the 
joints of the fourth foot present the same characters 
as in the female, except that the marginal sete of the 
