NYCTIPHANES SIMPLEX. 229 
Remarks.— This species is allied to NV. australis G. O. S., but differs in several 
features. In order to point out and illustrate these differences I have given on 
Plate 6 figures of the antennular peduncles of both sexes and of the copulatory 
organs of N. australis; the figures were drawn from two cotypes of Sars. 
The leaflet from first joint is much smaller than in NV. simplex and consider- 
ably broader than long (figs. 3a-3d), subtriangular, with the outer margin convex 
and very oblique, and it terminates in a more or less acute tip bent upwards and, 
in one of the specimens drawn, somewhat forwards and placed almost above the 
inner margin of the joint, furthermore no transverse, vaulted part is seen at the 
outer side below the base of the leaflet. The antennular peduncles in the male 
are still somewhat thicker, those of the female still more slender than in NV. simplex. 
In the male (fig. 3a and 3b) a high, compressed, keel-shaped protuberance is seen 
near the end of second peduncular joint, and the third joint is somewhat thicker 
than in N. simplex, with about six minute hairs, but no stiff setae, on the inner 
side. The copulatory organs (fig. 3e) have the most distal part of the inner 
lobe considerably broader than in N. simplex, the proximal half of the outer 
margin of this lobe differs in the shape of the protuberances from that species, 
but the most important difference is shown by the median lobe (Im.), which in 
N. australis has the lateral process placed as in N. simplex, but the lobe itself 
projects along that process to its end; if this lobe had been cut off opposite 
the insertion of the process we would have the structure found in N. simplez. 
The female examined of N. australis is 13.5 mm., the male 15 mm. 
Distribution.— In 1894 Ortmann (Bull. Mus. Comp. Zodl., 25, p. 100) enum- 
erated nine localities for Nyctiphanes australis: —Gulf of Panama, Galapagos, 
Gulf of California, and some Stations in the Northern Pacific between San Fran- 
cisco, and the Hawaiian Islands. From the U. 8. National Museum I have 
received specimens from these Stations and an examination gave the result, 
that the two specimens from ‘“‘Survey” Sta. 54 and “Survey” Sta. 74, both 
Stations in the North Pacific between San Francisco and the Hawaiian Islands, 
are males of Euphausia recurva H. J. H., while the specimens from the seven 
other Stations belong to N. simplex and not to N. australis. The latter species 
is hitherto only known from the sea around the Southeastern part of Australia; 
in 1911 I established N. capensis on the specimens mentioned by Stebbing in 
1905 and 1910 as taken off Cape St. Blaize, South coast of Africa, and by him 
referred to N. australis. 
