106 H. J. HANSEN. 
second joint, but while the largest of them, which is a high 
protuberance, is situated on the lower surface of second joint, 
the others vary as to place. ‘The arrangements for the 
brood differ greatly in various genera. 
The character used for dividing allthe generaof the groupinto 
two portions, viz. the absence or existence of an articulation of 
exp. of plp.%, is certainly practical, but scarcely very important ; 
the two portions arising from this division can scarcely be 
considered natural sections. But on the other hand, it is 
impossible to give a better division, because at least three 
genera—Cy modocella (Pfeff.), Amphoroidea (M.-Edw.), 
and Cassidinopsis (n. gen.)—are not very closely allied either 
to each other or to the other genera. For these reasons I 
do not attempt to sub-divide this group into sections with 
names, while such division is most natural in the two other 
groups of the sub-family. 
a. Exp. of plp unjointed. (Not seen in Nesicopea, but 
this genus is closely allied to Dynamene.) 
(a) Basal joint of antennule of usual shape, not expanded 
in a free plate. 
(t) Urp. always with an exp. at least half as long as endp. 
and sometimes (in males) very elongate. 
(§) Male with a pair of processes from sixth thoracic seg- 
ment, its abdomen with a circular foramen (sometimes situated 
on a low cone) connected with the end by a short narrow slit ; 
uropods have exp. much longer than endp.; no appendix 
masculina on endp. of plp.2. Female without processes, abdo- 
men with a foramen connected with the end either by a slit 
which is only somewhat narrower than, and not marked off 
from, the foramen, or by a quite linear sht; rami of urp. 
lamellar, subsimilar in length ; mouth-parts exceedingly meta- 
morphosed, marsupial lamellee exceedingly large and the brood 
in the marsupium itself. 
(1) Dynamene (Leach) (Nesa (Leach) ). 
($$) Both sexes without processes on thorax, but the last 
abdominal segment with two blunt “ processes situated one 
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