CRUSTACEANS alone differing by having only three teeth and a tubercle on the front half of its long side margin and a little tooth close to the hinder ex- tremity of it. The section Catometopa, or crabs with a downward bent front, to judge by existing records, has only two representatives in Sussex. Of these Goneplax angulata (Pennant) is marked rare in the Natural History of Hastings} This species resembles Corystes cassivelautnis in the great length of its chelipeds, but its second antenn;r are short and its carapace is broader than long. Its name by interpretation is a plaque or tablet with angular corners. The hind corners however of the carapace are rounded, but the front ones, against which the long eye-stalks fold down, are exceedingly sharp. The family Goneplacids is spoken of as showing a close resemblance to the Cyclometopa, being an instance of those transitions which make classification difficult and the study of nature interesting. Among the Pinnotherida?, Pinnotheres pisum (Linn.), which, in contrast to the preceding species, is a little short-armed, round button of a crab, is noted by the Natural History of Hastings as common,^ and this may very well be, since its well known habit of taking lodgings with a mussel, an oyster, or some other obliging mollusc, gives it a kind of freedom to be found in all waters where its hosts foregather. With species of the section Oxyrrhyncha the county is fairly well supplied. In these the front is usually more or less sharply produced, and ' the beak ' is often divided into two acute horns. The family Inachids contains seven of the species here requiring notice. Macropodia rostrata (Linn.) was obtained from Sussex by Bell, who calls it Stenorynchus phalangium (Pennant), although by his own confession these are not its earliest names. He quotes from Mr. Hailstone the statement that ' it is very common at Hastings, both among the rocks on the shore, and in deep water, and is occasionally caught in the trawl- net in vast numbers : of sixty-eight specimens brought up at once the proportion of males to females was as two to one.' ^ Macropodia tenuirostris (Leach) was taken by Bell in prawn pots at Bognor. He says, ' this elegant species may be readily distinguished from the former by the long attenuated rostrum, by the existence of a small spine on the epistome immediately behind the basal joint of the external antennse, and by a series of minute spines on the inner part of the arm : the body is altogether more elongated, and the spines more acute, but in other respects the characters are nearly the same.' * For comprehending these distinctions it is necessary to remember that the so-called ' arm ' of the chelipeds is the long joint which immediately precedes the three ter- minal joints called wrist, hand and finger. The fixed thumb of the hand and the movable finger form the chela or nippers of a crustacean. The epistome or over-mouth is to be found on the under side of the crab, just above that important 'buccal area' which is more or less closed in by the external maxillipeds. The species M. tenuirostris was long identified with Inachus longirostris, Fabricius, but Miss M. J. Rathbun 1 Nat. Hist. Hastings, p. 41. '^ P- 4i- ^ P- +■ ^ p. 6. 251
