35. t. 3.) has recently
described a species of this genus from Madagascar, under the name of A.
MADAGASCARIENSIS, which is nearly allied to the Van Diemen's Land
species, in the shortness of the frontal process, the spines on the sides
of the second abdominal segment, and in the lobes of the tail; but it
differs from it in the length of the claws, and other particulars.
Madagascar appears to be the tropical confines of the genus.
2. The Western Australia Cray-fish. ASTACUS QUINQUE-CARINATUS, t. 3. f.
3. - Carapace smooth, rather convex, and with three keels above; the beak,
longly produced, ending in a spine, simple on the side and produced into
a keel on each side behind; the central caudal lobe rather narrow,
indistinctly divided in half, and like the other lobes flexile at the
end, the lateral lobes with a central keel ending a slight spine; the
hands elongated, compressed, smooth, with a thickened, toothed, inner
margin, which is ciliated above; wrist with two conical spines on the
inner side.
Inhab. Western Australia, near Swan River.
3. The Port Essington Cray-fish. ASTACUS BICARINATUS, t. 3.f.
2. - Carapace smooth, rather flattened, with a keel on each side above in
front; the beak longly produced, flattened, three toothed at the top;
hands rather compressed, smooth, thinner and slightly toothed on the
inner edge; the wrist triangular, angularly produced in front; the
central caudal lobes with two slightly diverging keels continued, and
like the others thin and flexible at the end, the inner lateral lobes
with two keels, each ending with a spine.
