70 
Rev. A. M. Norman on Crustacea Cumacea. 
branch, its first joint very short and unarmed, second having 
one simple and two plumose spines on the inner margin and 
terminating in two very long spines. The spines of the inner 
margin of the inner branch are all tipped with a little cilium; 
and the two long spines of the outer branch, which I have 
called “plumose,” are of very peculiar structure : their basal 
portion under the microscope appears as if furnished with 
stiff hairs ; but the apical portion would perhaps be more cor¬ 
rectly described as pectinate. 
The peculiar production of the rostrum in this species is a 
very remarkable feature. 
From the wide distance apart at which the only two known 
examples were found, it is probable that Leucon longirostris 
will prove to be widely diffused over the bed of the Atlantic 
Ocean. 
2. Leucon nasicus : Kroyer. 
1841. Cuma nasica, Kroyer, Naturhist. Tidsskrift, vol. iii. p. 524, pi. vi. 
figs. 31-33. 
1843. Leucon nasica , Kroyer, Naturhist. Tidsskrift, and. rsekkes vol. ii. 
pp. 189, 209, pi. ii. fig. 5, a, b ; id. Voyages en Scandinavie &c. pi. iii. 
fig. 2, a-o. 
1855. Leucon nasica, Lilljeborg, CEfvers. af Vetensk.-Akad. Forh. 
p. 121. 
1864. Leucon nasicus, G. 0. Sars, Om Cumacea, Vid. Selskab. Forhandl. 
p. 53. 
A single specimen taken by the 1 Porcupine ’ expedition in 
1869 in the Minch. Not before known as belonging to the 
British fauna. 
3. Leucon serratus , n. sp. 
1876. Leucon serratus, Norman, MS., ‘Valorous’ Report, Proc. Royal 
Soc. vol. xxv. p. 212. 
Female. Carapace much longer than the free segments of 
cephalothorax and very deep, the depth being subequal to the 
length, exclusive of the rostrum; dorsal margin boldly arched, 
having a continuous unbroken serrated line throughout its 
length ; serrations triangular, small posteriorly, and gradually 
increasing in size forwards ; rostrum, viewed laterally, short, 
deep, triangular, directed horizontally in front of the point 
where the dorsal line sweeps down to meet it, its edge with a 
few elongate serrations ; antero-lateral corner produced for¬ 
wards and outwards in wing-like form; lateral margin with 
about ten elongated triangular serrations, of which the three 
or four front (on the wing-like expansion) are much larger 
than the rest. Total length of pleon (without uropods) not ex¬ 
ceeding that of the cephalothorax. Upper antennae very small, 
just reaching to the end of the rostrum. First feet having 
