1382. ] ON CRUSTACEANS FROM MAURITIUS, 339 
at the end of the cell of the primaries, and passing in a bow to the 
anal angle of the secondaries, beyond this towards the outer margin 
fading into grey, apices of primaries narrowly tipped with black : 
the underside resembles that of the male; but the colours are paler, 
and the base of the wings is of a tawny yellow instead of a reddish 
orange. 
EXPLANATION OF PLATE XIX. 
Fig. 1. Upperside of Agrias stuarti ¢. 
2. Underside of Agrias stuarti 3. 
5. Upperside of Agrias beatifica 2. 
4. Underside of Agrias heatifica 2. 
6. On some Crustaceans collected at the Mauritius. 
By Epwarp J. Migrs, F.L.S., F.Z.S8. 
[Received March 15, 1882.] 
(Plate XX.) 
The Crustaceans which I have now the pleasure of bringing before 
the notice of the Society were obtained at the Mauritius by M. Robil- 
lard, and recently forwarded by him to the British Museum. They 
are:—(1) a fine Spider-crab, described below as Nawia robillardi, 
which was dredged at a depth of 30 fathoms [that such a large and 
interesting a species should have remained so long unnoticed is very 
remarkable; and J can only account for it on the supposition that this 
crab lives habitually at considerable depths, and hence has escaped 
the notice of collectors of the littoral forms, most of which are 
well known]. (2) an example of Neptunus sieboldi, A. M.-Edwards, 
a swimming crab hitherto a desideratum to the national collection ; 
and (3) several specimens of a Hermit Crab which I think is Ceno- 
bita perlata, M.-Edwards: although having the inferior surface 
of the joints of the first three legs very hairy, these specimens in 
all other particulars coincide with M.-Edwards’s brief description in 
the ‘ Histoire naturelle des Crustacés’ (ii. p. 242, 1837), and with 
the excellent figure in the large illustrated edition of Cuvier’s ‘ Régne 
Animal’ (pl. xliv. fig. 1). 
In order to complete the account of the Crustaceans received from 
the Mauritius through M. V. de Robillard, I have added a brief 
notice of a fossorial Crustacean of which two examples, both unfor- 
tunately imperfect, were sent two years ago to the British Museum 
by the same collector, and which I propose to designate Callianassa 
mauritiana, 
Naxra (NAXIOIDES) ROBILLARDI, sp, n. (Plate XX. fig. 1.) 
The carapace is subpyriform, rather convex, and covered with 
long stout conical spines ; of these spines about 13, situated on the 
gastric region, are arranged in three somewhat irregular trans- 
verse series, behind and in front of which are some smaller spines : 
