18 AUSTRALASIAN ANTARCTIC EXPEDITION. 
There seems little reason to doubt that the two specimens on which the foregoing 
description is founded represent the two sexes of the same species; that which I take 
to be the female, possesses however, no spinous armature on any of the limbs, and the 
fifth pair of feet may perhaps be immature. 
The species here described I very doubtfully refer to the genus Spinocalanus 
of Giesbrecht. The fifth pair of feet, according to Sars, are absent in the female, 
whereas in the present species they are present in a very rudimentary form, unless 
indeed, the figure here given be taken to be an immature male. Moreover, the third 
and fourth pairs of feet of S. Giesbrechti are by no means so profusely spiniferous as in 
the typical form, agreeing more closely with those of Racovitzanus Giesbrecht. 
The specimens were taken by the tow-net at sunrise, Station 5, off Macquarie 
Island. 
Genus STREPTOCALANUS gen. nov. 
Anterior antennze 23 jointed not geniculated, the internodes of most of the 
median joints constricted, the joints about as long as broad, except the eighth which is 
much longer; mandibles well developed as regards the palp, but wanting as to the 
cutting blade which is altogether absent or remains as a mere nodule; fifth pair of feet 
in the male two branched, the branches simple but very unequal in length. 
STREPTOCALANUS TYPICUS sp. nov. 
(Plate V, figs. 1-9.) 
Pseudocalanus psymeus, Mrazek, p. 508, Plate V, figs. 2-7, 7a. 
The pecular curve of the fifth foot when seen laterally, together with the con- 
spicuously beaded character of the anterior antenne are sufficient to indicate this 
species at a glance. The biting plate of the mandible seems to be usually absent, but 
‘n some specimens there is an amorphous process which represents that part of the 
limb; the exopodites of the swimming feet are all three-jointed, the endopodites of the 
first pair one-jointed (incompletely divided), the second pair two-, the third and fourth 
three-jointed. The fifth pair is two-branched, the larger right branch made up of five 
digitiform subovate segments, the smaller branch of two similar segments. Outer 
branch of the posterior antenna much longer than the inner. Length of male 1-075 
mm. Female unknown. Found very sparingly in Stations 3, 7, 8, 10, 11. 
The swimming feet resemble rather closely those of Spinocalanus, but are 
altogether without spines, and in other respects there is little in common between the 
two. But it is evident that the species referred doubtfully by Dr. Mrazek (loc. cit.) to 
Pseuocalanus pygmaeus G. O. Sars, is closely allied to the Streptocalanus here described. 
The admirable figures given in “ Arktische Copepoden,” leave little or no doubt 
on the matter. Perhaps I may be forgiven if I suggest that the figure of the mandible 
of “ Spinocalanus Schaudinni”’ may have been accidentally transferred from “ Pseudo- 
calanus pygmaeus.” Jt is wholly unlike the mandible of a typical Spinocalanus, and 
might very well stand-for that of Streptocalanus. 
