384 A HISTORY OF RECENT CRUSTACEA 
flattened and ciliated. The incubatory pouch in the female 
is generally under the first four segments of the perzeon. 
The swimming joints above described resemble those 
found on some of the swimming crabs, and differ strikingly 
from what is customary among the Isopoda. To this 
family, indeed, the titie of equal-legged animals is singu- 
larly inappropriate. 
Munnopsis, Mickael Sars, 1861, has the body suddenly 
constricted and slender behind the fourth perzeon-segment. 
The second antennez are very elongate, with the peduncle 
six-jointed. The mandibles are acuminate, with a second- 
ary plate on the left, but not on the right mandible, with- 
out molar, and with a three-jointed ‘palp.’ The first and 
second limbs of the pereeon are short, rather robust, sub- 
prehensile, the two following pairs enormously elongated ; 
the three following pairs are natatory, without a seventh 
joint. The arrangement of the pleopods corresponds with 
that already described in Janira. The uropods are slender, 
single-branched. Munnopsis typica, Michael Sars, the type- 
species, has a very extended boreal distribution in deep 
water on muddy ground. Hansen says that in the second 
antenne the long fourth and fifth joints of the peduncle 
are immovably fused. In these organs the flagellum is 
nearly as long as the peduncle, and the two together are 
about five times the length of the body. By the great 
elongation of the fifth and sixth joints in the third and 
fourth limbs these equal about three times the body’s 
leneth. Munnopsis australis, Beddard, with no ‘ palp’ to 
the mandibles, and with the marsupium arising apparently 
only from one segment of the perzeos, must probably be 
referred to a separate genus. 
Eurycipe, Sars, 1864, has the body not abruptly con- 
stricted. The second antennz are very elongate, with six- 
jointed peduncle. The mandibles have a spine-row, molar, 
and three-jointed ‘ palp,’ but no secondary plate on either 
mandible. The first pair of limbs are rather short, the 
next three pairs are long, and the last three pairs are nata- 
tory, with an unguiform seventh joint. The pleopods 
are as in the preceding genus. The uropods are short, 
