52 MR. T. BELL ON THE CRUSTACEA 
nished with a series of small denticulations beneath, as in the genus Pisa; the female 
is without them. 
Colour lightish brown; the hands mottled. 
Length of the carapax 2 inches 2 lines, including the rostrum which is 4 lines long 
and 2 broad; breadth of the carapax 2 inches nearly. 
Two specimens, a male and a female, were obtained by Mr. Cuming. 
Notwithstanding the length and spinous form of the rostrum, the more elongated 
form of the carapax, and the moderately developed character of the claws, I cannot but 
consider this species as belonging to the genus Mithraz, as all its essential characters 
correspond with that group. It may perhaps be considered as offering a step towards 
the genus Pisa, not only in the characters already mentioned, but also in the denticu- 
lations on the under surface of the nails in the male; a character which, although con- 
sidered as essentially distinguishing the last-named genus, can only be ranked as of very 
secondary importance, as in the present species it constitutes but a sexual distinction, 
the male possessing it, and the female being wholly destitute of it. 
Mirurax Ursus. 
Tab. X. Figg. 2, 3. 
Mithr. testé granulatd, verrucoso-tuberculatd, rostri dentibus obtusis, granulosis ; tuberculis 
octo pone rostrum, et sex circum orbitas ; manibus levibus. 
Junior. Cancer Ursus, Herbst, I. p. 217, t. viv. f. 86. 
Hab. ad Insulas Gallapagos dictas. 
Mus. Soc. Zool., Bell. 
Carapax in the young specimens somewhat pyriform, in the adult nearly orbicular, 
granulated, and with numerous warty tubercles, of which there are four immediately 
behind the rostrum, forming a square, and four a little behind them similarly disposed. 
The latero-anterior margin has three or four strong prominent tubercles each with one 
or two smaller ones at its base. Rostrum projecting, formed of two strong rounded 
teeth, each terminated by a warty tubercle. Orbits with six similar tubercles, of which 
that over the inner canthus is the most prominent. Eyes globose, smaller than the base 
of the peduncle. 
The exterior antenne hairy in the younger specimens ; the basilar joint with a large 
tubercular tooth at its outer angle, the apex of which, like all the other tubercles in 
this species, is granulated or warty. The interior antenne, the external pedipalps, and 
the abdomen do not materially differ from those parts in the other species of the genus. 
The anterior pair of feet are, in the female, a little longer and more robust than the 
others ; the arm and wrist covered with prominent tubercles ; the hand smooth, the 
fingers in this sex, and in young males, serrated at the margin, but without a tubercle. 
(It is probable, that in the adult male the hands are more robust and the fingers fur- 
