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are thickly covered with hair. There is, according to Sars, a possibility, which, however, S. I. Smith thinks an improbability, that the species may be the same as one earlier but all too briefly described by Stimpson, from the coast of Florida, under the name Scyra umbonata. The specimen taken by the Porcupine was first described as Amathia Carpenteri, but the genus Amathia, Roux, has a pre-occupied name which has in consequence since been changed, by S. I. Smith, to Anamathia, and Professor A. MilneEdwards discovered that the species Carpenteri could not be included in that genus. At the same time he noticed its likeness to Stimpson's species above mentioned, and framed for it the new genus Scyramathia. From the foregoing remarks it will easily be understood what suggested the composition of this generic name, but it must not be forgotten that Scyramathia belongs to the family Maiidæ, whereas Anamathia stands in the previously described Inachidæ, and Scyra (though to the exclusion of Stimpson's species umbonata) is a genus belonging to the next family, the Pericerida.

Family 3.-Pericerida.

The eyes are retractile within the small circular and well-defined orbits, which are not incomplete as in the Maiidæ. The basal joint of the second antennæ is well developed, and constitutes a great part of the inferior wall of the orbit, the joint being in general much enlarged.

The family contains about twenty genera.

Pericěra, Latreille, 1829, of which the type is Pericera cornudo (Herbst), 1804, has been despoiled of many of its species by Miers, who has transferred them to Macrocæloma, a new genus which he instituted in 1879. Of the species Macrocoloma trispinosa (Latreille) Mr. Ives says that Yucatan specimens when alive are of a bright scarlet colour. In the Challenger species, Macrocoloma concava, Miers, from Bahia and Fernando Noronha, the body and limbs are covered with a short close pubescence and with some longer curled hairs. Its colour in spirit is

yellowish-brown, but this is little or no guide to what its colour may have been when living. The specific names in this genus ought to have either masculine or else neuter terminations, but many naturalists seem to suppose that any generic name ending in -a is a feminine form, which is far from being the fact.

In this family the genus Libinia, Leach, 1815, contains several species, and Mithrax (Leach), Latreille, 1817, a very large group. Of Libinia emarginata, Leach, Miss Mary Rathbun, in her recent revision of the Periceridæ, says that in Long Island Sound occasionally this species by its numbers 'so interferes with the steam oyster dredgers that work is abandoned until the crabs (which are known to the oystermen as "spiders") have passed over.'

Legion 2.-Parthenopinea.

The basal (or true second) joint of the second antennæ is very small and embedded with the next joint in the narrow gap between the front' and the inner orbital angle, the infraocular space being mainly occupied by the inferior wall of the orbit.

Family 4.-Parthenopida.

The eyes are usually retractile within the small circular and well-defined orbits; the lower wall of the orbit is continued to within a very short distance of the 'front.' The second antennæ are very slender; the basal joint does not as in the Periceridæ constitute a great part of the inferior orbital margin, but is very small, seldom reaching the 'front,' and with the next joint occupies the narrow gap intervening between the front' and the inner angle of the orbit. (In Ceratocarcinus the antennæ are completely excluded from the orbits.)

Some fifteen or twenty genera are reckoned in this family, of which only one is known in the waters of Great Britain.

Eurynome, Leach, 1814, has not yet received many

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additions to the type species Eurynome aspera (Pennant), for though the names scutellata and boletifera have been given to forms taken in the Mediterranean, it is probable that they are not distinct from, or at most are only varieties of, the species found on the British coasts. It is, as might be guessed from the names, a species rough with warts or tubercles. The walking-legs are short, but the chelipeds in the male are elongate, being nearly twice the length of the body according to Bell, but according to Leach three times its length. Eurynome tenuicornis, Malm, from Bohuslän, Guilmarsfjord, is there found together with Eurynome aspera.

Partherope, Fabricius, 1798, has in its type species, Parthenope horrida (Linn.), an animal of truly remarkable appearance. It is recorded from the West and East Indies, and has been called the great Warty Crab or stigmatised as the Lazy Crab. Its carapace is pentagonal, broader than long. While this and the legs are covered with warts and spines, the pleon is said to be full of pits, almost as if eaten through. The chelipeds are large and long. From the picture of it given by Herbst one might suppose that it was intended to look like a piece of light-red sandstone overgrown here and there with green algæ.

Lambrus, Leach, 1815, unlike the two preceding genera, suffers from no paucity of species. So numerous indeed are they that in 1878 Professor A. Milne-Edwards deemed it expedient to subdivide Lambrus into ten genera, including in the number Solenolambrus, Stimpson, and Mesorhoea, Stimpson. The species are distributed over all the warmer seas of the world, and some occur in the Mediterranean. Of these Lambrus macrochēlos (Herbst), meaning the Lambrus with long chelipeds, justifies its name, but almost puts its body out of countenance, seeing that the arms in question are nearly four times as long as either the length or breadth of the carapace. In Lambrus intermedius, Miers (see Plate IV.), from the Corean Seas and Torres Strait, the disproportion between legs and trunk is less exaggerated. In the genus at large it is remarked that, apart from larval metamorphoses, so many variations

of form are undergone during progress to the adult condition, that, without a considerable series of specimens, young and old of the same species must often almost inevitably be considered as distinct.

Heterocrypta, Stimpson, 1871, contains but three species, and those of small size but singular appearance. One of these, Heterocrypta Maltzani, Miers, which has been taken at Goree Island, at the Azores, and off Senegambia, is also an ornament of the Mediterranean, having been taken by the Travailleur at a depth of about 250 fathoms off Toulon. The Mediterranean form was at first named Heterocrypta Marionis, after the distinguished French zoologist, but it has since been found to be the same species as Heterocrypta Maltzani.

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CHAPTER IX

TRIBE IV.-OXYSTOMATA

THE carapace is convex or depressed, with the anterolateral margins arcuate or orbiculate; or even subglobose; or more or less oblong, with subparallel or slightly convergent margins (Dorippidae). The epistome is very much reduced or rudimentary. The buccal frame is more or less triangular, nearly always produced and narrowed forwards with the margins anteriorly convergent. The afferent channels to the branchiæ open either behind the pterygostomian regions and in front of the chelipeds, or, more rarely, at the antero-lateral angles of the palate (Leucosiidae). The efferent channels open at the middle of the endostome which is produced forwards. There are six to nine pairs of branchiæ. The first antennæ fold longitudinally or obliquely. The third maxillipeds have the fifth joint articulated at the inner or the outer front angle or at the apex of the fourth, beneath which it is often concealed. The verges of the male are exserted either from the surface of the sternal plastron or more usually from the bases of the fifth pair of legs, which are either adapted for walking or for swimming, or are feeble and raised upon the dorsal surface of the carapace.

It is the narrowing anteriorly of the buccal frame or mouth-cavity' that gives the name of 'sharp-mouths' to this tribe, which is divided into four families, the Calappidæ, Matutidæ, Leucosiidæ, and Dorippida.

Family 1.-Calappida.

The afferent channels to the branchia open behind. the pterygostomian regions and in front of the chelipeds.