As in the head so in the peræon, the middle of the back is comparatively smooth, but other parts are armed with a multitude of very unequal spines, the largest occupying prominences on the flanks of the first four segments. In the first three there are also small subdivided spines nearer the middle, and the fourth has a notable pair of backward curving spines near its hind margin. The remaining segments of the person and the whole pleon are pretty well covered with little spines, some of which are much smaller than others. The pleon has two decided, but apparently quite unsutured, transverse dorsal furrows in advance of the telsonic segment. The latter carries no very strong spines, and slopes rather abruptly down to a smoothly rounded apex. The dividing line between the head and first peræon segment is well marked.

As noted by Beddard for other species, the side-plates of the fourth peræon segment here evidently help to support the ovigerous lamellæ. They here form a narrow strip directed obliquely backward, with a dentate process directed forward from the fore margin. In advance of these the segment displays a pair of little rounded wings.

The first antennæ have a spine-like tooth on the short broad first joint; the two following joints are much narrower than the first but not much shorter, together scarcely as long as the one-jointed flagellum, which has a couple of filaments at four or five points of the margin, and an apical group of four.

The second antennæ have a tooth process on the short first joint, a close set group of six such processes on the longer second, and seven or eight more sparsely arranged on the much longer third. joint; the fifth joint is a little shorter than the fourth, both being very long and slender, with a few setules; the flagellum is fivejointed, about three-fifths as long as the last joint of the peduncle and longer than its first three joints combined. On one of these appendages there is a little apical tooth, which may represent a sixth joint.

The upper lip is somewhat unsymmetrical, with a decided emargination. The mandibles are robust, with the cutting plate quadridentate, the accessory plate at least in one mandible tridentate, the spine-row consisting of few spines, the molar powerful. The first maxillæ have three plumose setæ on the inner plate, and eleven spines on the outer plate of one maxilla, while on that of its partner there seemed to be only ten. The lower lip and second maxillæ are of the usual character. The maxillipeds have the second joint surmounted by a broad plate which seems to form two leaves; to what extent these are separated remains doubtful; on neither could

any coupling-hooks be perceived; the fifth joint of the palp is well. developed, but blunt, not at all finger-like. The epipod is broad throughout, not lanceolate.

The first gnathopods are small, with a denticle high up on the second joint, the fourth joint short and bulb-like, the sixth nearly as long as the second, the finger broad, with its nail almost hidden. among long serrate setæ. They carry marsupial plates folded within the following pair. The second gnathopods and first peræopods are similar to the second peræopods, but shorter and with small dentate side-plates. All three pairs carry very extensive marsupial plates. The second to the fifth joints are furnished with a variety of spine processes, the fourth having a specially blunt apical process. The fifth joint is as long as the second in the second peræopods, but exceeds it in length in the two preceding pairs of limbs; the sixth joint is slender, not so long as the fifth, and ends in a slender nail-like finger which is itself tipped by a long spine; the third to the sixth joints carry numerous long setæ.

The last three pairs of peræopods are as usual distinct in character from the preceding limbs, but similar one to another, although successively shorter. In the third peræopods the second joint is considerably longer than the sixth, but little or not at all longer than that joint in the two following pairs. This second joint is notable for its variety of spine-processes, among which are one or two that are blunt; the third joint is also armed, but the remainder are content with a few needle-like and feathered spinules and setules; the finger is rather robust, with a little tooth on the inner margin in advance of the nail.

The first pleopods have the peduncle armed along one margin with a long row of thirteen or more little glittering teeth, and on the opposite or inner margin with about eight hooked spines.

The uropods are diversified with numerous little denticles on the outer surface; the distal part of the hinge margin is fringed with plumose setæ. The exposed ramus is very small, rather broader than long, with a little subapical spinule; the concealed ramus is about as long, but less than half as broad, and has four graduated slightly curved spines on the distal margin.

The length of the specimen was 17 mm., not including the second antennæ, which also measured 17 mm.

The spots and dendritic markings, and the extraneous substances, including foraminifera, entangled among the processes of the body and limbs, cause some difficulty in distinguishing the number and shapes of the various ornaments.

Locality. Cape St. Blaize, N. by E. 73 miles; at a depth of 125 fathoms; bottom, sand and shells.

The specific name, meaning branch-bearing, from κλácos, a branch, refers to the peculiar processes on the head and trunk.

In A. alcicornis Whitelegge describes two prominent spines on the frontal region of the head, each with an accessory spine immediately below, a stoutish bifurcated spine on each side of the first peræon segment, and four short antler-like spines on each of the second and third segments. Thus the pair of long antlered processes on the back of the head in the South African species are evidently not present in the Australian. In the latter the third joint of the first antennæ is only one-third as long as the second; the maxillipeds have large lanceolate epipods and the first two joints of the palp subequal; the first gnathopods have the finger curved; the sixth joint in the first and second peræopods is said to be progressively shorter than that of the second gnathopods, whereas in the African species this joint is as long in the first peræopods as in the preceding limbs, and the other differences are sufficiently shown by the drawings here given. Whitelegge's specimen, with second antennæ wanting, was an adult female, body about 10 mm. long. He describes at the same time four other new species of Arcturus from South Australia, three of which also have dentate limbs.

TRIBE EPICARIDEA.

1893. Epicaridea, Stebbing, History of Crustacea, p. 392. 1897. Epicaridea, Hansen, Bulletin Mus. Comp. Zool. Harvard, vol. xxxi., p. 111.

1898. Epicaridea, Sars, Crustacea of Norway, vol. ii., p. 193.

1905. Epicaridea (or Bopyroidea), H. Richardson, Bulletin U.S. Nat. Mus., No. 54, p. 497.

1906. "Bopiridi," Nobili, Acc. R. Sci. Torino, vol. xli. (extr.),

FAMILY BOPYRIDE.

1893. Bopyrida, Stebbing, History of Crustacea, p. 408. 1898. Bopyrida, Sars, Crustacea of Norway, vol. ii., p. 195.

1900. Bopyrida, Bonnier, Travaux de la Station zool. de Wimereux,

vol. viii., p. 218.

The name is still elastic. The limits of the family, which have been variously stretched and contracted, approach a settlement in

Therein he accepts two

M. Jules Bonnier's authoritative work. divisions of the Epicaridea, called respectively Cryptoniscina and Bopyrinæ, thus using terminations commonly regarded as indicative of sub-families under which to group numerous families. To his Bopyrinæ he assigns the Dajidæ, Phryxidæ, Bopyridæ, and the Entoniscidae, of which the first three were provisionally retained by Sars in the family Bopyride. The family is restricted by Bonnier to parasites in the branchial cavity of decapod crustaceans.

GEN. BATHYGYGE, Hansen.

1897. Bathygyge, Hansen, Bulletin Mus. Comp. Zool. Harvard, vol. xxxi., p. 122.

1900. Bathygyge, Bonnier, Travaux de la Station zool. de Wimereux, vol. viii., p. 290.

1905. Bathygyge, H. Richardson, Bulletin U.S. Nat. Mus., No. 54, pp. 499, 537.

Hansen does not separate the generic from the specific characters. Bonnier says that the pleon of the female suffices to characterise the genus, as it has no side-plates, and the uropods, like the pleopods, are biramous.

BATHYGYGE GRANDIS, Hansen.

Plate XXXIII.

1897. Bathygyge grandis, Hansen, Bull. Mus. Comp. zool., vol. xxxi., p. 122, pl. 6, figs. 2-2c.

1900. Bathygyge grandis, Bonnier, Travaux zool. Wimereux, vol. viii., p. 291, fig. in text.

1905. Bathygyge grandis, Richardson, Bull. U.S. Nat. Mus., No. 54, p. 537, fig. in text.

Hansen's account, on which the other two depend, was based on a male specimen and the fragment of a female. The latter consisted of the pleon with the terminal part of the peræon bearing three legs on one side and two on the other. They had occupied the branchial cavity of Glyphocrangon spinulosa, Faxon, taken from a depth of 676 fathoms, in lat. 21°15' N., long. 106° 23' W.

That the South African specimens here figured belong to Hansen's genus and species seems exceedingly probable, although, as Hansen had only a portion of a female at his disposal and has not figured that portion, some element of doubt remains. The carapace enormously dis

of the African Glyphocrangon on the right side was torted by the swollen marsupium of its female tenant. Her eggs form

an immense mass, and owing to the very distended condition of the marsupium its first plates are more visible on the dorsal than on the ventral aspect. Also one or two of the lateral lobes are forced back over the head. As in Bonnier's genus Orbione, the person is of great breadth, the general outline of the body being almost circular. The rather small pleon is turned sharply to the left, with the first three segments very distinct. The remainder may be equally so, but their smaller size and pale colour make the observation difficult. The maxillipeds make a near approach to those figured by Bonnier for Pleurocrypta hendersoni and P. porcellana, and by Hansen for Cryptione elongata. The little unjointed palp is here rather thickly fringed with setæ on the inner margin. My dissection was not sufficiently successful to show the articulations displayed in Hansen's figure, so that my drawing does not distinguish the maxilliped itself from that hind border of the head which carries at its angle the two fleshy lobes represented.

The limbs of the peræon, though longer, are less robust in the female than in the male. The sixth joint is oblong with a slight curvature, the small palm having a little emargination almost masked by the tightly clasped finger.

Concerning the pleon, Hansen says: "Pleural plates not developed. The pleopods quite soft, of medium size, decreasing conspicuously in size from before backwards and attached to the lateral margin; each pleopod consists of a short peduncle and two lamellar oblong rami; the outer ramus much larger than the inner one. The uropods. biramous; the outer ramus a little smaller than the outer of the fifth pleopod, the inner ramus very short, almost rudimentary. The pleopods are curled to such a degree that it would have been impossible without much construction to draw a sketch of the abdomen." Rashly, perhaps, in face of the last clause, I offer an outline of the pleon in dorsal view, so far as I have been able to make it out, for comparison with the verbal description.

The male was attached to the left side of the female, as shown in the figures, with his pleon adjacent to her third peræon segment, and his head placed on the right side of her uropods. The relatively great size of this sex, the incisions separating the segments of the peræon, the pleon without pleopods or uropods, the antennæ and mouth organs, the limbs with deeply concave palm, are all in agreement with Hansen's figures and description. Here the front margin of the head is evenly rounded, not flattened, as in Hansen's specimen; but the difference is trivial. Here the pleon on the underside shows a partial longitudinal and two transverse folds. Also there