270 The Malacostraca of Durban Bay 
The account given of this species by Desmarest is in translation as 
follows: ‘ Length six lines [12°5 mm.]; carapace extremely depressed, 
smooth, semi-transparent, in form of an equilateral triangle ; anterior 
angle or rostrum a little rounded and raised, concealing the eyes and 
the base of the antenne ; chelipeds and ambulatory legs very elongate, 
slender and smooth ; hands very long, having their fingers of equal 
force, a little inflated towards the end ; a little spine on the extremity 
of the hind face of the last four perzeopods ; colour corneous.” 
Before identifying the South African specimen with Desmarest’s 
description above rendered, on the possibility of its proving to be a 
new species, the name equilateralis had occurred to me as appropriate. 
It is in shape very nearly allied to the form which de Haan in his 
text calls Ocypude ( Klamene) unguiformis, but on his plate 29, fig. 1, 
Inachus ( Elamene) unguiformis, which Milne Edwards in 1853 placed 
in anew genus 7'riyonoplax, clearly, as Alcock suggests, a synonym 
of Elamena. Paulson’s Hlamena mathwi seems to be an independant 
member of the genus, and Heller’s E/amene mathei is rather doubtful, 
but Ruppell’s Hymenosoma mathei, if his figure may be trusted, cannot, 
as I now think, possibly be referred to the present species. 
The chief, perhaps the only, reason for distinguishing de Haan’s 
species from Desmarest’s is that in de Haan’s figures the fingers of the 
chele are represented very much shorter than the palm. But Alcock, 
describing specimens from the Andamans, says that these fingers are 
‘“‘as long as the slender subcylindrical palm.” In our specimen the 
relation of the movable finger to the palm is about 24-29 in length. 
When Desmarest speaks of ‘‘a little spine on the extremity of the 
hind face of the last four legs, ‘“‘I suppose him to mean the apical 
prolongation of the fourth joint which might pass for an extremity 
- when the three following joints are folded towards the preceding joint. 
The flat, semi-transparent carapace measured 10 mm. from the 
acute apex to the truncate hind margin, with a breadth of 11 mm. at 
the rounded off hind corners. The female pleon is broader than long, 
of six segments, slightly lobed along the centre, which is distally 
convex. The four pairs of biramous pleopods are long and slender. 
The ova were not numerous and had not been deposited on the pleon. 
The eyestalks are short and stout, just allowing the cornea to appear 
beyond the edge of the carapace. Tho second antenne are very slight 
in structure. The palp of the mandibles has a long curved second 
joint, while the first and third joints are exceedingly small, the third 
scarcely reaching beyond the slightly advanced apex of the second. 
In all three maxillipeds the exopod has a narrow terminal joint tipped’ 
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