Tribe Astacidea.
34. Astacopsis serratus (Shaw).—This animal has been given different names by different naturalists, on account of some of them getting large and some small specimens. In large examples the abdominal somites are each armed with a row of strong conical spines, but in young specimens these are either rudimentary or quite absent. There are also other differences. It is distributed with some variation over most parts of New South Wales. The colour, which also varies, is most commonly of a deep red. Attains a length of 18 in. Huxley mentions it in his book, 'The Crayfish,' under the name of "Australian Crayfish."
Tribe Penæidea.
35. Penæus canaliculatus (Oliv.).—This is truly a handsome species, having, when alive, the most delicate tints, and sometimes growing to the great length (for a Prawn) of 10 in. It is one of the principal Prawns of the Sydney fish-market, but is not so common as its congener, P. esculentus. Port Jackson; Botany Bay; Japan.
36. Penæus esculentus (Hasw.).—The common Prawn of Sydney, and caught in great numbers with the nets. This genus is remarkable for the large membranous appendage attached to the base of the first pleopod of the male, and called by SpenceBate the "petasma," or curtain. In the female this appendage is quite rudimentary. Port Jackson; Port Darwin. Incidentally it might be mentioned that when the term "Prawn" is mentioned the genus Penæus is meant; Palæmon, to which the English Prawn belongs, not being known here as an article of diet.
Tribe Caridea.
37. Rhynchocinetes typus (M.-Edw.).—This species surpasses in beauty any crustaceans that I have ever observed, the body being a beautiful semi-transparent tint, with here and there spots of light blue dotted over it. The chelæ are red with white dactyli. Altogether it is most disappointing to see their magnificent colours fade so much when the animals are preserved. They frequent semi-dark situations below low-tide mark, and if taken and put in a bottle containing sea-water die in a very short time, though
