
8 RECORDS OF THE S.A. MUSEUM 
jecting posterior corners, which are rounded and unarmed. The right first an- 
tenna is considerably longer than the left (which resembles that of the female) 
extending nearly to the end of the caudal rami, though having only 22 segments. 
The complicated fifth lez approaches in its strueture most closely to those 
of tasmanica and longicornis, but has a much more slender left exopod. The 
structure of this leg is illustrated from both anterior and posterior surfaces, and 
its appearance from the right side is also shown. The right exopod is very long, 
and when extended reaches beyond the caudal rami. 
In the female this species is very like expansa in its general shape, though 
the posterior thoracic processes are directed outwards more strongly than in that 
species and the body is not so slender. The fifth legs in both sexes are quite dis- 
tinct from Sars’ species. 
Famity PSEUDODIAPTOMIDAE Sars 1902. 
Sars, 1902, p. 73. 
The family was created by Sars, without definition, for two genera, Pseudo- 
diaptomus and Poppella, which ‘‘together form a natural group somewhat inter- 
mediate between the Diaptomidae and the Temoridae.’’ This arrangement was 
followed by A. Scott (1909) and by Friichtl (1924) but both Sewell (1924, 1932) 
and Wilson (1932) include Pseudodiaptomus in the Diaptomidae. 
Genus Pssupop1aptromus Herrick 1884. 
Scott, A., 1909, p. 116; Wilson, 1932, p. 101. 
The systematics of this genus, which includes numerous species ranging from 
purely fresh water to marine conditions, have been discussed by Sewell (1924, p. 
784; 1932, p. 233) and by Brehm (1924, p. 84). The latter gives a key which in- 
cludes most of the species. Sewell (1924) suggested a division of the species into 
two groups, dependent upon. the relative length of the terminal spines on the fifth 
leg of the female. In one group these spines are sub-equal and comparatively short, 
while in the second group at least. one of these spines is ‘‘nearly equal in length to 
the whole limb’’. 
The species found here comes into the first group and is very close to salinus 
Giesbrecht (1896), which has been recorded from the Mediterranean to the Indian 
Ocean, but differs in several respects, particularly in the male. The tendency for 
the species of this genus to have a very localized distribution, particularly where 
the conditions are less saline, justifies this species in being regarded as distinct 
from the marine form with its wide distribution. 
The salinity at Blanche Harbour, where this form was taken, is presumably 
lower than that of ordinary sea water, judging by the presence of Gladioferens in 
the same collection. 
PSEUDODIAPTOMUS CORNUTUS Sp. Nov. 
Occurrence. III, 16 females (2 ovigerous), 11 males, 5 young. 
Female. Length 1-20—1-24 mm. Body symmetrical, head fused with first 
segment, the latter bearing a pair of rounded knobs dorso-laterally on the posterior 
margin. The fourth and fifth segments are fused, and the posterior corners pro- 
duced into spine-like processes extending beyond the middle of the genital seg- 
ment. The urosome is 4-segmented, the genital segment being the longest and 
having a ventral swelling. There is a group of spinules laterally on the left 
side of this segment. The caudal rami are three times as long as wide. The first 
