Danielssenia sibirica Group — Wilson 
endopod of male leg 2 (the extended apical 
process of D. stejanssoni, absent not only in 
sibirica but also in other species of the genus). 
DISTRIBUTION and ecology: Type locality 
not designated. Sars records collections made in 
August-September, 1885-1886, from three 
localities of the coastal regions of Siberia and 
islands between the Laptev and East Siberian 
seas, including the lower part of the River Yana 
and the New Siberian Islands. Of these, only 
one collection was taken from the sea, the 
others having been made in what must have 
been brackish situations. Yashnov’s record from 
Wrangell Island, overlooked by Lang (1948), 
was based on 1929 collections from brackish 
water. The range of distribution of D. sibirica 
as now known is therefore from about 72 °— 
74° N and 135°-180° E, and it should be 
classified as a brackish water-marine species. 
Danielssenia stefans soni Willey, new description 
Figs. 1-3 
Danielssenia stefans soni Willey, 1920, pp. 
3k (reference to), 5k, 8k, 35k (occur- 
rences) ; p. 39k, figs. 60-67 (original 
description) . 
Danielssenia stejanssoni : Jespersen, 1939^ 
pp. 78, 100: Table 7 (occurrence; identi- 
fied K. Lang) ; 1939^, pp. 47, 57: Table 
1; p. 58 (occurrence). — Lang, 1948, p. 
282: Table 5 (leg setation) ; p. 298 (tax- 
onomic group; key) ; p. 301, fig. 146.6 
(figs., diagnosis from Willey) ; p. 1570 
(zoogeography) . 
Danielssenia stepans soni (incorrect spelling) : 
Mohr et ah, 1961, p. 221 (occurrence; 
identified M. S. Wilson). 
Danielssenia: Wilson and Tash, 1966, p. 574 
(occurrence) . 
All of Willey’s material was from the region 
of Bernard Harbour, Canada. No type material 
is deposited in the National Museum of Canada 
or the U. S. National Museum (personal cor- 
respondence, Dr. E. L. Bousfield and Dr. T. E. 
Bowman). Willey’s description gives only a 
few figures and notes, some incomplete or dif- 
fering from Alaskan specimens; many of the 
notes are written as comparisons with Sars’s 
437 
nearly complete textual and illustrative account 
of D. sibirica, or of other species. Lang’s brief 
diagnosis appears to be based on Willey’s ac- 
count without addition of any new information 
from the east Greenland specimens he identified 
for Jespersen. The few differences between 
Willey’s account and mine are, I believe, logi- 
cally regarded as errors or omissions rather than 
variations from the specimens of the type local- 
ity. Comments on these and Lang’s interpreta- 
tion, where different, are inserted in paren- 
theses in the following descriptive text. Willey’s 
eight figures illustrate these appendages: an- 
tenna (apical segment endopod S ) ; maxil- 
liped; leg 3 9 endopod; leg 5 2 (2 figs., 
normal and aberrant) ; leg 2 S (2 figs, en- 
dopod, entire and enlarged segment 3) ; leg 3 
$ endopod. 
OCCURRENCE OF ALASKAN SPECIMENS: 
NUWUK LAKE (or pond), Point Barrow Penin- 
sula (71°23'N, 156°28'W) ; collectors, R. 
Lewis and J. Tibbs; in three samples taken 
during ice-free period, I960: (1) bottom 
sample, station at 0.9-1. 2 m depth, August 1: 
12 $, 1 $ ; (2) horizontal plankton tow 
south to north, from 0.3 m to surface, August 
11: 1 ovigerous $ ; (3) plankton tow, center 
of lake, from 3.7 m to surface, August 11: 3 
$,1 S . COAST OF CHUKCHI SEA, SOUth of 
Cape Thompson; plankton samples from two 
ice-free, landlocked, shallow lagoons (depth 
not more than 3 m) ; June 21, I960; collector, 
J. Tash: (1) Mapsorak Lagoon (68°02'N, 
165°21'W): 3 $; (2) Pusigrak Lagoon (68° 
01'N, 165°18'W) : 1 $. 
DESCRIPTION of female: Habitus (Fig. I A) 
— Length range Nuwuk Lake specimens, dorsal 
midline, base of rostrum to end of caudal rami, 
1.25-1.4 mm. Anterior part of body a little 
shorter and broader than posterior. Distal mar- 
gins of metasome segments armed with fine 
spinules. First urosome segment (somite of 
leg 5) with small lateral processes armed with 
spinules (Figs. I A, 2 E). Genital segment 
divided by cuticular sclerotization ventrally 
(Fig. 1C) and in part dorsally (Fig. 1 A); 
ornamented by a few spinules dorsally but not 
ventrally. External genital area as in Figure 
1C; genital pore prominent, set at top of 
