W. T. CALMAN. 



serrated on its lower edge. Antcimulos witli the inner ramus of cfinsiderable size, 

 longer than the first segment of outer ramus. Lfropods a little longer than the last 

 two somites together, peduncle shorter than the suljequal rami and having five spines 

 on its inner edge. Endopod with ten spines on its inner edge, without setae on its 

 outer edge, the proximal segment twice the length of the distal. 



Fig. 1. — Lciicon aiistraHs, adult female, from the side, appendages omitted. 



Occurrence. — W.Q., June 15, 1902. D-net. 



Remarks.— Among the thirteen species at present referred to the genus Lcucon, 

 four have the inner ramus of the antennule of considerable size, at least equal in 

 lensth to the first segment of the outer. Of these, L. lom/irostri.^-, Sars, L. 

 tenalrostris, Sars, and L. sijjhoiiatus, Caiman, have the antemial notch narrow and tlie 



Fig. 2. — Lcucon auslralis, carapace and antennule. 



Fig. 3. — Leucon auslralis, 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 antenual 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 tliau half the length of the proximal segment. 



