8. Neptunus sanguinolentus (M.-Edw.).—This species is rather common, and specimens of a small size are extremely abundant. But few of them arrive at a large size. This falling-off, I think, is mainly due to the attacks of its congener the quarrelsome and almost ubiquitous N. pelagicus, which species is a great check on the diffusion and growth of very many of the pelagic Crustacea. Not being so good—from an epicurean point of view—as N. pelagicus, it is but little sought after. It has an extremely beautiful appearance, the carapace showing iridescent colours, and having on it three spots like drops of blood, surrounded by bluish white rings, one on either side on the epibranchial regions and one almost on the posterior border of the carapace, over the intestinal region. It leads a pelagic life, and is widely disseminated.
9. Charybdis cruciatus (Herbst.).—This is, in my opinion, the most beautiful of our Crustacea. When fresh, its rich tints cannot be surpassed by anything in Nature. It may be seen occasionally in company with N. pelagicus at the fish-market, but is very uncommon. I have never found it in its young state.
10. Scylla serrata (De Haan).—This is the largest Crab to be seen in the Sydney fish-market. Like N. pelagicus, it is pelagic, but is not nearly so common. The carapace is generally of a dark green colour. It has a wide distribution, reaching from Japan to Australia. Around the anterior border of the carapace there is a row of sharp conical spines. Any refractory prisoner is quickly put an end to by being pressed against these.
11. Thalamita sima (M.-Edw.).—Does not attain a large size, and is essentially pelagic. It is rather common in our bays and harbours. Carapace and chelae shortly setose, and of a greenish hue.
12. Thalamita admete (Herbst.).—This is a very small pelagic Crab. I have observed it in tiny pools in rocky situations at Port Jackson.
13. Nectocarcinus integrifrons (M.-Edw.).—Though adapted for a free-swimming existence, this species lives to a great extent on the bottom in shallow water, amongst seaweed. It is not of uncommon occurrence for green Fucus to be found growing on its legs and carapace, which are very setose. East coast of Australia and New Zealand.
14. Platyonychus bipustulatus (M.-Edw.).— This pelagic spe-
