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.

Inhab.  Port Essington, Mr. Gilbert.

The A. AUSTRALASIENSIS, Milne Edwards, Crust ii. 332. t. 24. f. 1—­5. agrees with this species in the form of the beak, but the keels on the thorax are not noticed either in the description or in the figure; and the caudal lobes in the figure appear most to resemble A. FRANKLINII.

As the genus ASTACUS is now becoming more numerous in species, it may be divided, with advantage, into three sections, according to the form of the caudal lobes; thus:—­

A. The central caudal lobes divided by a transverse suture into two parts, both being hard and calcareous, and with a small spine at the outer angle of the suture (PATAMOBIUS, Leach) as A. FLUVIATILIS of Europe, and A. AFFINIS of North America, with an elongated rostrum, and A. BARTONII of North America, with a short rostrum.

B. The central caudal lobe continued hard and calcareous to the end, as ASTACUS FRANKLINII of Van Diemen’s Land, and A. MADAGASCARIENSIS of Madagascar; both have a very short beak, and the second abdominal ring spinose.

C. The central caudal lobe continued or only slightly divided on the middle of each side; but it and all the lateral lobes are thin and flexible at the hinder parts, as ASTACUS Quinque-CARINATUS, and A. BICARINATUS of Australia, and A. CHILIENSIS of Chili.

Catalogue of reptiles and fish,
found at king George’s sound,
by Deputy assistant commissary-general Neill,

In A letter to J. E. Gray, Esq.  British museum, London.

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