20 Prof. J. C. Schisdte on the Structure of 
long, narrower in the fore part, with a small Dab irsere on 
the outer margin, which touches the stem of the mandibles, 
‘and is somewhat vaulted, but does not by any means cover in 
the stems of the second pair of maxille so completely as is the 
case in dga. ‘The stems of the two maxillipeds meet, as 
in 4¢ga, with their even inner margins, and likewise fit in 
between the middle ridge of the sphenoid plate and the second 
pair of maxille, by means of a crest on their upper surface ; 
but this is considerably narrower than in dga. ‘The palpus 
is small, pointed, biarticulate, slightly curved inwards, with a 
row of small hooked spines on the inner or lower edge of the 
terminal joint. The upper or outer margin of the palpus is 
also in Cymothoa arranged to fit into a groove in the stem of 
the mandible, and forms the side margins of the mouth-tube. 
In the female, on the contrary, the maxillipeds are con- 
verted into a pair of thin lamelle, which are almost entirely 
covered from beneath by the first pair of plates of the egg-bag, 
‘and which do not reach so far that the palpi can form part of 
the mouth-tube; the cardo, besides, has a foliaceous inward- 
turned prolongation ; and, as the inner margins of the stems, 
moreover, are not quite rectilinear, the stems do not meet ac- 
curately along the middle line of the skull, and it is only on 
a short piece that they fit in above between the ridge of the 
sphenoid plate and the second pair of maxille. Each of the 
stems, besides, expands on the outer side into a large, thin, 
rounded leaf, which reaches forward a considerable distance 
beyond the small palpus, of which only the last joint has a 
few thorns at the apex. 
In both sexes the maxillipeds are without lobes: the inner 
corner of the stems certainly presents a little eminence, which 
is particularly easily aed in the male; but it lacks sete, 
and can consequently hardly be looked upon as a lobe. 
Of course this great sexual difference in the structure of the 
mouth entails a corresponding difference in the part taken by 
the maxille of the second pair in the composition of the mouth- 
tube. 
The peculiarity of the second pair of maxille in Cymothoa 
consists in this, that the lobes are neither separate lobules as 
in 4fga, nor turned back in the shape of collars, but they 
coalesce with one another, are soft, swelling, and by slight 
longitudinal nthe divided into small oval cushions (three 
on each maxilla), which together form the posterior part of the 
orifice of the mouth-tube. The outermost cushion has on the 
outside and at the apex a scattered number of small pointed 
warts; the intermediate and innermost cushions have no 
warts except on the margins, but have besides in their fore 
