98 H. J. HANSEN. 
of the head. Peduncle of antennule three-jointed, of antennz 
five-jointed. Mouth-parts, biting or gnawing, never really 
suctorial; second joint of maxillipeds at least in males and 
immature specimens without external expansion; mouth-parts 
in females with brood rather frequently strongly metamor- 
phosed and useless for nutrition. Thoracic segments seven, 
all free ; marsupial lamellee only on second, third, and fourth 
“epimera,” rarely wanting (section Cassidinidi). All pleopods 
lamellar; all endopods, and at least the exopods of first and 
second pairs unjointed; at least both rami of plp.' and plp.? 
fringed with long plumose sete, and at least in all two rami 
of the posterior pairs (both rami of plp.® or the endp. of plp.* 
and plp.5) without such sete, and specially adapted for 
breathing. Sixth segment large. Uropods with the rami 
unjointed, these, at least in the females, generally depressed, 
sometimes one of them wanting; in Vireia the uropods are 
wanting. The body can be rolled more or less completely 
into a ball or can be folded. 
The family is divided into three sub-families : 
1. Limnoriine.—Mandibles stout; lacinia mobilis at 
most rudimentary, without plate on the left mandible; molar 
process wanting; palp three-jointed. Maxillule with the 
inner lobe well developed; maxillz with the three distal lobes 
very short, but yet well developed. Maxillipeds with a single 
hook on the lobe from second joint; epipod large, longer than 
broad. Epimera not marked off from first thoracic segment ; 
second to seventh epimera a little movable. Abdomen con- 
sists of six movable segments. Plp.* and plp.* have both 
rami furnished with long plumose marginal sete, as have also 
plp.! and plp.*?; rami of plp.® without marginal setz, respira- 
tory ; exp. of plp.® without squamiferous areas or tubercles. 
Endopod of urp. movable. (The brood in the marsupium 
itself; no sexual difference in the mouth-parts.) 
2. Spherominz.—Mandibles, at least their basal half, 
stout; lacinia mobilis well developed, with plate on left 
mandible ; molar process generally well developed (wanting 
in the section Ancinini) ; palp three-jointed. Maxillule with 
ee 
