2 W. T. CALMAN. 
serrated on its lower edge. Antennules with the inner ramus of considerable size, 
longer than the first segment of outer ramus. Uropods a little longer than the last 
two somites together, peduncle shorter than the subequal rami and having five spines 
on its inner edge. Endopod with ten spines on its inner edge, without setze on its 
outer edge, the proximal segment twice the length of the distal. 
Fic. 1.—Leucon australis, ADULT FEMALE, FROM THE SIDE, APPENDAGES OMITTED. 
Oceurrence.—W.Q., June 15, 1902. D-net. 
Remarks.—Among the thirteen species at present referred to the genus Leucon, 
four have the inner ramus of the antennule of considerable size, at least equal in 
length to the first segment of the outer. Of these, LZ. longirostris,* Says, L. 
tenuirostris, Sars, and L. siphonatus, Calman, have the antennal notch narrow and the 
Fic, 2.—Leucon australis, CARAPACE AND ANTENNULE. Fic. 3.—Leucon australis, LAST SOMITE AND UROPOD, 
antero-lateral margin serrated above the notch. L. septemdentatus, Zimmer, from 
Tierra del Fuego, resembles the present species in the form of the antennal notch, but 
differs in the truncate pseudorostrum, in having the serrations of the dorsal crest 
confined to its anterior part, and the distal segment of the inner ramus of the uropods 
much less than half the length of the proximal segment. 
