seven eggs, which, as so commonly in deep-water species, were extremely large. From one of these Mr. Spence Bate extracted a young animal, and this proved to be not unlike the young of the lobster at the same stage, but more advanced, thus so far confirming the view that the great size of the deep-water ova is in relation to the more than usual advancement of the embryo before it is hatched.

Family 4.-Thaumastochelide.

The carapace is produced to a flattened point or rostrum. The first pair of antennæ have on each peduncle two long subequal flagella; the second have a scale or exopod. The first pair of trunk-limbs are chelate, unequal, somewhat unsymmetrical; the small second pair are chelate, subequal, symmetrical; the outer branch of the uropods is larger than the inner. The branchiæ are filamentous, cylindrical.

To this family Spence Bate assigns only two genera, one of which is British.

Thaumastochēles, Wood-Mason, 1874, is appropriately named 'the creature of wonderful claws.' The type species, Thaumastocheles zaleucus (von Willemoes Suhm) (see Plate X.), was taken by the Challenger from a depth of 450 fathoms in the West Indies, along with a great number of other curious marine animals frequenting the globigerina ooze in that locality. It is blind, and not only without eyes but without eye-stalks, unless perchance the latter are represented by a pair of tubercles projecting from the 'front.' The front' is sub-membranous and translucent, and Spence Bate supposes that the optic nerve may terminate so closely behind it as to receive impressions of light. But though there are no eye-stalks, there are excavations in the anterior margin of the carapace corresponding to orbits, and also depressions in the first pair of antennæ such as eye-stalks often rest in. The inference then is clear that eye-stalks once existent have been lost, and this probably from their being detrimental instead of useful to a burrowing creature. The burrowing character is in

ferred from the general agreement of the species with others that are known to be fossorial. This agreement is exhibited more especially in the tail-fan, but other features favour the notion of such a habit. The flagella of the first antennæ, fringed with long fine hairs, may assist in keeping open a breathing hole. The anterior outlet of the branchial chamber is protected against intrusive particles by a joint of the first maxillipeds so disposed as to serve for an operculum. Of the very unequal first legs the limb on the right side has the thumb and finger monstrously developed into a pair of combs carrying about sixty unequal teeth apiece, and, as Spence Bate observes, ‘it appears probable that when partially closed it has the power of raking the neighbourhood to a considerable distance, and so entrapping small animals and other material from which the blind creature has the power of selecting its food.' As this extremely elongate hand could not convey the food to the mouth, the short second and third pairs of legs are also conveniently chelate. The fifth pair are the same, at least in the female, but in these the minute chela buried in a thick brush of fur probably has some function other than that of assisting its mistress to feed.

Calocaris. Bell, 1853, has but a single species, Calocaris Macandreæ, Bell, found in the waters of Ireland, Scotland, and Norway. It is still comparatively rare, as might be expected of an animal which burrows at depths of 80 and 150 fathoms. Its habits would seem to be tolerably sluggish, since specimens are sometimes overgrown with a small zoophyte, the polyzoon Triticella flava, Dalyell, which can scarcely serve any purpose of concealment. The eyes are present but have lost their pigment, so that vision is probably dim. The first pair of legs are unequal, but not strikingly so. These and the next pair are chelate, while the remaining three pairs are simple. Spence Bate makes it a character of the family that the tail-fan has the outer plates much larger than the inner, but, though this is true of Thaumastocheles, it scarcely applies to Calocaris.

A NEW TRIBAL NAME

191

CHAPTER XIII

TRIBE III.-SCYLLARIDEA

THE first antennæ carry two flagella; the second have no scale. The trunk-legs are six-jointed through coalescence. The first pair are not much larger than the second, and simple or scarcely subchelate; the three following pairs are simple, and the fifth pair is simple in the male, more or less minutely chelate in the female. The branchiæ are well developed; epipodal plates on the first joint in the first four pairs of trunk-legs have podobranchiæ attached to them as distinct plumes. All these same limbs have arthrobranchiæ, and the last four segments of the trunk have pleurobranchiæ. The first segment of the pleon is without appendages.

In this tribe Spence Bate says that the ova are very small, and that the young are hatched in a Phyllosomaform. With the Astacidea and Stenopidea it forms what he calls the normal group of the Trichobranchiate Macrura. It contains two families, the Scyllarida and Palinuridæ, and the tribal name given it by Spence Bate was Synaxidea (see p. 46), derived from a new genus Synaxes, which he considered to combine some of the features of both families. As Synaxes is itself a synonym, it was not possible to retain the tribal name derived from it, while Heller's term loricata adopted by Paulson, Boas, and others, is not in conformity with the names of the neighbouring tribes.

Family 1.-Scyllaridæ.

The carapace is depressed, with orbits for the eyes excavated in the dorsal surface. The second antennæ are