FAMILY SPH ROMIDA. 109 
Uropoda similar in both sexes ; endp. laterally expanded, very 
much broader and a little longer than exp. Both sexes 
similar, without processes; female with normal mouth-parts 
and the brood in internal pouches. 
(10) Cassidinopsis (n. gen.). 
Group C. Spheromine platybranchiate. 
This group is sharply defined from the two preceding ones, 
but its twelve genera show much variation, not only in 
general aspect, but in several structural features. It is, 
however, not necessary to produce here a more detailed 
account of the differences, because the group is divided into 
four sections which are natural and sharply limited by a set 
of characters, and a perusal of the diagnoses of these groups 
may convey a Sufficient idea on the points essential. It may 
be added that the arrangements for the development of the 
brood differ strongly in the sections, but the mouth-parts 
seem never to be metamorphosed in the female. 
It is an interesting fact that some of the genera of the 
eubranchiate Spherominze comprise three or four and some 
of the hemibranchiate genera a large number of species, but 
each of the platybranchiate genera comprises at most two 
and the majority only one species hitherto described. Most 
of the genera are, besides, very rare in collections. 
The characterisations of the four sections are given before 
the diagnoses of the genera in order to facilitate comparison. 
(a) SectionCampecopeini.—Body rather vaulted ; thorax 
and abdomen not expanded laterally, without any row of 
short hairs on the lateral margin. Eyes well developed. 
The two proximal joints of the antennule fitted in excavations 
on the head and not expanded plate-like in front. Mandibles 
with the masticatory process well developed. Anterior pairs 
of legs without prehensile hands. Endp. of plp.! at most 
somewhat longer than broad. Both rami of plp.® with long 
plumose setze on their distal margin ; exp. two-jointed. Plp.4 
and plp.® subsimilar in aspect, with their rami respiratory ; 
