
122 RECORDS OF THE S.A. MUSEUM 
This species, which is named after Miss Patricia Mawson, somewhat resembles 
the male of tribulis, but the seulpturing is very different, and the joints of the 
maxillipeds and peraeopods are of different proportions, 
Although mawsonae obviously belongs to the exsculpta group, it has no 
posterior transverse carina (mere suggestion only) and no quadrangular de- 
pression on the side. C. candida (male only known) has a faint posterior trans- 
verse carina according to Zimmer (1929, p. 9, fig. 12-18), the inferior portion of 
the carapace is not marked off by an oblique longitudinal ridge running back 
from below antennal tooth, the lower ridge of the ‘‘quadrangle’’ does not con- 
tinue right to the hinder edge of the carapace, and the upper margin of the 
second pedigerous somite is steeply oblique, not elevated as in mawsonae. 
Acceptance of the fact that extreme sexual dimorphism occurs in tribulis 
leads to consideration of the possibility of an association between the swarming 
of mawsonae males and that, a week later at the same place, of newly moulted 
usitata females with fully developed but empty marsupium. 
In the case of tribulis, however, there are definite features linking the sexes 
—the presence of a post-ocular tuberele at all stages, the distinctive character of 
the dorsal carina of the carapace, the fossorial limbs, ete. There are no such 
parallels in mawsonae and usitata, but on the contrary the sculpture of the cara- 
pace and the fossorial limbs are markedly different; the setae of these peraeopods 
are much longer in usitata, and in both sexes of tribulis, than they are in maw- 
sonae (ef. D in fig. 42 and 43). 
Cycuaspis usitaTa Hale. 
Cyclaspis usitata Hale, 1932, p. 549, fig. 1. 
Further material throws a little more light on this species, which is ap- 
parently abundant in parts of St. Vincent Gulf, South Australia; as previously 
suggested it is possible that wsitata is the female of candida Zimmer (1921, p. 9, 
fig. 12-18) from North-Western Australia. 
Like the members of the exsculpta group in general, it is a highly calcified 
species. The type (10 mm.) is the largest example so far secured. In this the 
second transverse carina of the carapace is interrupted on the back. 
Adult females. A large number of females, 7 mm. or so in length, was col- 
lected at Brighton, South Australia, by Miss Patricia Mawson, using a submarine 
light. In these the second transverse carina of the carapace is continued across 
the back to the median carina, although it is faint immediately alongside the 
last-named. The anterior transverse ridge, as it crosses. the back, has a well- 
marked median projection, sometimes tooth-like; it is more distinct inferiorly 
than in the larger type female. 
First antenna stout and relatively large, with basal joint shorter than second 
and third together; third little longer than second; flagellum very short. 
The basis of the second peraeopods is a little longer than the rest of the 
limb and its inner edge bears a row of stout plumose setae; ischium and merus 
each with two subapical setae but no spines; carpus short, together with propodus 
as long as merus, and with one stout apical spine; longest terminal spine of dac- 
tylus as long as dactylus plus propodus. Fossorial peraeopods stout; carpus not 
much longer than merus and with three subterminal setae which with propodal 
seta reach well beyond apex of dactylus (fig. 43, D). 
Pedunele of uropods distinctly shorter than rami, with plumose hairs, on 
inner margin; exopod a little longer than endopod, with a long row of inner 
plumose hairs, and with apex subacutely rounded; endopod with inner edge 
serrate. 
