FAMILY SPHMROMIDA. 108 
end obtuse or with some small teeth. Side of abdomen not 
expanded below the lateral margin of thorax. Tip of abdomen 
rounded, 
(1) Spheroma (Bosc). 
(tt) Mandibles aberrant, having the cutting process very 
elongate (fig. 5a), its distal part widened and divided by a 
deep triangular incision into two oblong, plate-shaped, dis- 
tally acute processes. Lateral wall of abdomen considerably 
expanded, directed downwards, and extending a good deal 
below the lateral margin of thorax. Tip of abdomen trian- 
gular, acute. 
: 2) Hemispheroma (n. gen). 
p g 
(8) Maxillipeds with the lobes from fourth, fifth, and sixth 
joints at least rather long. Three anterior parts of thoracic 
_ legs without stiff natatory sete. LHxp. of plp.? two-jointed. 
Marsupial lamellz small, far from reaching each other at the 
mesial line. 
(t) ‘Last thoracic segment unarmed in both sexes. Hnd of 
abdomen at most somewhat produced, but not acute. 
(3) Exospheroma (Stebb.). 
(tt) Last thoracic segment in the male with a slender mesial 
process. End of abdomen somewhat or very considerably 
produced, subacute. (In the male both rami of the uropods 
are exceedingly large plates.) 
($) End of abdomen subsimilar in both sexes, very consider- 
ably produced, with a real groove on the lower side of the 
produced part. 
(4) Isocladus (Miers). 
(§§) End of abdomen in the female somewhat produced, in 
the male strongly produced with a pair of lateral notches, so 
1 The genera Exospheroma, Isocladus, and Zuzara (with Cycloi- 
dura as a synonym) are so closely allied that the females can scarcely be 
separated, while it is easy to refer the adult males to their respective genera. 
When more species are known it will probably be necessary to unite them, 
preserving the name Zuzara for the genus. If that be not done it will be 
necessary to establish a new genus for Spheroma scabriculum (Hell.), 
and perhaps some other species. 
