NEBALIADiE. 
35 
The thorax is divided into eight slender segments, 
completely concealed within the carapace ; and the abdo- 
men consists also of eight rings, but which are consider- 
ably longer and narrower than the preceding. The first 
four of these are concealed by the carapace, and the other 
four project beyond it. To the first four we find attached 
the natatory feet (t. II, f. 1 c), consisting of four pairs. 
These project from beyond the carapace at its inferior 
posterior portion, and are composed each of an elongated 
basilar joint, which gives origin to two rather long, strongly- 
ciliated branches and a very short, simple one. To the 
fifth and sixth joints we see attached two pairs of what 
have been described as rudimentary members, and which 
resemble very much the fulcra or supporters of the ex- 
ternal ovaries in the Cyclopidae. The penultimate joint 
wants these organs, but the last gives off at its extremity 
two rather long appendages, forming the tail. These 
caudal laminae are smooth on their edges, and are fur- 
nished with one long slender filament, and three or four 
shorter ones, not plumose. 
We know very little with regard to the habits of this 
genus. Otho Fabricius tells us that it carries its eggs 
under its thorax during the whole winter; that they 
begin to hatch in the month of April, and that the young 
are born in May ; they are very lively, he adds, and ad- 
here to the mother, who appears then to be half dead. The 
adult swims in a prone state, using its hinder feet to propel 
it through the water. They are not very active. Montagu 
informs us, that when moving in the water the superior 
antennae are in constant motion as well as the abdominal 
feet, but that the inferior antennae are usually motionless 
and brought under the body. They are found, according 
to Leach, on the south-western and western coasts of 
England, under stones that lie in the mud, amongst the 
hollows of the rocks; and Mr. M'Andrew dredged it 
from a considerable depth amongst the Shetland Isles. 
This family contains only one British genus. 
