228 Mr. A. O. Walker on the Isopoda and Amphipoda 
Head having a triangular projection, on which is a tubercle, 
behind the bases of the upper antennz; these have the last 
joint of the peduncle more than twice as long as the penulti- 
mate. Lower antennz wanting in all the specimens. Man- 
dibles with a prominent molar expansion and divided cutting- 
edge as in M. longicornis, Hansen; palp very large and 
prominent, with a jiamellar terminal joint. Maxillipedes with 
a prominent lobe on the outer margin of the inner plates ; 
palp with the fourth joint large and rounded. 
First body (mesosome) segment rather wider than any of 
. the succeeding three; coxal plates rather large, widening 
distally, so as to conceal the ends of thesegments. ‘The first 
of the last three segments (metasome) with a large oval 
tubercle on each side of a central cleft; the two following 
segments widening successively and marked by a transverse 
division ; the last has also a diagonal depression across each 
hinder angle. All the segments are rugose. 
All the ambulatory legs are wanting except the first joints ; 
these in the first pair of legs are twice as long and half as 
thick as those of the succeeding three pairs. The natatory 
legs have the fourth joint much expanded posteriorly and 
more than twice as large as the fifth joint, which is furnished 
with a small dactylus. 
Telson cordate, with a blunt carina; margins smooth. 
Uropods small and slender, 2-jointed, the second joint 
three times as long as the first. 
As G. O. Sars has pointed out (‘ Crust. of Norway, Isopoda,’ 
p. 133), Munnopsis longicornis, Hansen (‘ Isopoden &c. der 
Plankton Expedition,’ p. 8, pl. ii. fig. 1), differs in the struc- 
ture of the mandibles from the generic description, as does 
the present species. This also differs from both in the struc- 
ture of the maxillipedes and in the swimming-legs being 
provided with a dactylus; so that doubtless a new genus is 
required for its reception. As, however, it is impossible to 
define a genus satisfactorily from imperfect specimens, 
M. Sars’s genus must stand provisionally. Unfortunately it 
rarely happens that these Isopods are taken with their long 
and brittle appendages perfect. 
Seven specimens, probably all males. Length 7 millim. 
Net 4a, 1170 fath.; 4c, 920 fath. ; Af, 1275 fath.; 4h, 
1470 fath. ; 5 h, 1410 fath. (2 specimens) ; 5/, 1710 fath. 
The only other Isopods in the collection were a few 
Kpicarid larvee. 
