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sphæroma, while in the male a notch, as in the male Dynamenella (compare the diagnosis below) is observed; the specimen described by Heller is evidently a male. The female of the species seen by me cannot be separated from Exosphæroma, while the structure in the male alluded to is very curious. For various reasons I omit this form from the conspectus, hoping to obtain more material of allied species" (loc. cit. p. 102). In a further note Hansen says: "The genera Exosphæroma, Isocladus, and Zuzara (with Cycloidura as a synonym) are so closely allied that the females. can scarcely be separated, while it is easy to refer the adult males to their respective genera. When more species are known it will probably be necessary to unite them, preserving the name Zuzara for the genus. If that be not done, it will be necessary to establish a new genus for Sphæroma scabriculum (Hell.), and perhaps some other species" (loc. cit. p. 103).

GEN. SPHÆROMA, Bosc.

1802. Sphæroma, Bosc, Hist. Nat. Crust., vol. ii., p. 182.

1905. Sphæroma, Stebbing, Herdman's Rep. Ceylon Pearl Fisheries, pt. iv., Isopoda, p. 31.

1905. Sphæroma, Hansen, Quart. J. Microsc. Sci., vol xlix., pt. 1, p. 115.

SPHÆROMA TEREBRANS, Bate.

1866. Sphæroma terebrans, Bate, Ann. Nat. Hist., Ser. 3, vol. xvii., p. 28, pl. 2, fig. 5.

1904. Sphæroma terebrans, Stebbing, Spolia Zeylanica, vol. ii., pt. 5, p. 16, pl. 4.

1905. Sphæroma terebrans, H. Richardson, Bulletin U.S. Nat. Mus., No. 54, p. 282.

1905. Sphæroma terebrans, Hansen, Quart. J. Microsc. Sci., vol. xlix., pt. 1, p. 116.

There is a divergence of opinion between Miss Richardson and myself as to the distinctness of her species S. destructor from Bate's S. terebrans. Under the references given above, the arguments will be found fully stated for the opposing views. Hansen offers no decision.

Two specimens not distinguishable, as it seems to me, from those which Dr. Willey found in Ceylon, have been sent me from South Africa. Their depredations had been carried on at Gamtoos River

bridge.

FAMILY LIMNORIIDEÆ.

1850. Limnoriada, White, List of British Crust. in Brit. Mus., p. 68. 1880. Limnoriida, Harger, Rep. U.S. Fisheries, part 6, p. 371.

GEN. LIMNORIA, Leach.

1814. Limnoria, Leach, Edinb. Encycl., vol. vii., p. 433.

1904. Limnoria, Stebbing, Gardiner's Fauna Maldive and Laccadive Arch., vol. ii., pt. 3, p. 713.

Under the last reference a key is given to the four species of this

genus.

LIMNORIA LIGNORUM (J. Rathke).

1799. Cymothoa lignorum, J. Rathke, Naturh. Selsk. Skr., vol. v., p. 101, pl. 3, fig. 14.

1814. Limnoria terebrans, Leach, Edinb. Encycl. vol. vii., p. 433. 1857. Limnoria lignorum, White, Popular Hist. Brit. Crust., p. 227, pl. 12, fig. 5.

1904. Limnoria lignorum, Stebbing, Gardiner's Fauna Maldive and Laccadive Arch., vol. ii., p. 714.

Harger (loc. cit. p. 373) gives a synonymy of this species to the date of his work. The specimens sent me from the Cape, together with some of the timber they had been perforating, were obtained by Thomas Reeve, Esq., at Port Elizabeth. I have ascertained by dissection that they agree with the description and figures of the European species by Sars in his Crustacea of Norway. The maxillipeds have the lanceolate epipod shorter than the second joint, and the uropods have the little outer ramus unguiform. Harger figures these characters also for his North American specimens.

TRIBE VALVIFERA.

FAMILY ASTACILLIDEÆ.

1897. Astacillida, Sars, Crustacea of Norway, vol. ii., p. 88 (Arcturidæ, p. 86).

1901. Astacillida, Ohlin, Svenska Exp. till Magellansländ, vol. ii., p. 265.

1905. Arcturida, H. Richardson, Bulletin U.S. Nat. Mus., No. 54, p. 323.

1905. Astacillida, Stebbing, Herdman's Rep. Ceylon Pearl Fisheries, pt. iv., Isopoda, pp. 43, 46.

This family, as at present constituted, includes the genera Astacilla, Cordiner, 1793, Arcturus, Latreille, 1804, Arcturella, Sars, 1897, Antarcturus, zur Strassen, 1902, Pleuroprion, zur Strassen, 1903. Arcturides, Studer, has been transferred by Ohlin to a different family. In establishing Arcturella for his own Astacilla dilatata, Sars speaks of that as being "as yet the only known species of the genus." But I am inclined to think that both Leachia nodosa, Dana, 1849, and its close ally, Arcturus corniger, Stebbing, 1873, ought to be also referred to it, as well as Arcturus damnoniensis, Stebbing, already transferred by Norman in 1904. In 1902 zur Strassen transferred all the species from tropical and southern waters at that date reposing in the genus Arcturus, a score in number, to his new genus Antarcturus. If this cleavage be accepted, it will probably be followed by further generic subdivision, when some of the species have been described in more detail. Miss Harriet Richardson has given an analytical key to the North American genera of the family, among which Arcturella and Antarcturus are not included. In Astacilla and Arcturella the marsupium of the female is formed by a single pair of plates attached to the fourth person segment. In Pleuroprion Miss Richardson gives the character, "marsupium as in the genus Arcturus." But here a difficulty arises. According to Sars and Richardson, in Arcturus the marsupium is composed of three pairs of plates issuing from the second, third, and fourth segments of the peræon. Studer and Beddard, on the other hand, assign to this marsupium four pairs of plates, Studer in 1884 carefully figuring and describing the four pairs in the female of his Arcturus furcatus. This is in agreement with the new species about to be described. Unfortunately several species may have been assigned to Arcturus or Antarcturus without determination of this character. In such cases as those of Beddard's Arcturus spinifrons and Arcturus myops, when only males or what appeared to be males were obtained, such determination was obviously out of the question. Neither for Antarcturus oryx nor for Pleuroprion chuni, the typical species of his new genera, does zur Strassen give the number of the marsupial plates. It is therefore with some reserve that this character is employed in the following key:

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Finger of first gnathopod well developed-4.
(Side-plates of second to seventh peræon segments distinct
Side-plates of peræon segments not distinct

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Cordiner's work, to which the premier genus of the family is due, was published in numbers, unpaged, " without any regard to order or connection." The plate of Astacilla, &c., bears the date, "Published Dec. 28, 1793 by Peter Mazell Engraver No. 32 Bridges Street Covent Garden." An introductory address, signed by Charles Cordiner and Peter Mazell, is dated July 1, 1788. An editorial "Order of Publication. New arrangement," gives 24 numbers, placing the Astacilla in No. xxi.

GEN. ANTARCTURUS, zur Strassen.

1902. Antarcturus, zur Strassen, Zoologischer Anzeiger, vol. xxv., p. 686.

1903. Antarcturus, zur Strassen, in Chun, Aus den Tiefen des Weltmeeres, ed. 2, pp. 189, 561.

With regard to the distribution of the genus Arcturus in the unrestricted sense, zur Strassen observed that only in the cooler seas did its representatives ascend to the surface waters, and further, that a zone of the globe between 20° and 50° of northern latitude was quite without examples of this otherwise ubiquitous genus. Upon closer examination he convinced himself that the group of species living north of the empty zone was generically distinct from the group to the south of it. Accordingly with the type species drcturus baffini (Sabine) he placed A. tuberosus, Sars, A. longispinis, Benedict, A. glabrus, Benedict, A. beringanus, Benedict, and with slightly less certainty Arcturus hystrix, Sars, A. murdochi, Benedict, A. intermedius, Richardson. For the southern species he established Antarcturus and Antares, in the following year changing the latter name, which was preoccupied, into Pleuroprion, to which Miss Richardson, in 1905, transfers A. hystrix, A. murdochi, and A. intermedius. In Antarcturus the first person segment is not produced downward and forward to cover the mouth-organs and base of the first gnathopods; the finger of the first gnathopods is strongly developed, and these limbs themselves are fairly robust; the three following pairs of limbs are laterally prominent and geniculate.

These characters given by zur Strassen should, no doubt, be reinforced by the addition that the marsupium is composed of four pairs of plates, since the type species A. oryx is said to stand very near to

A. furcatus, Studer, in which, as already explained, the marsupium is so constituted.

The species A. myops, Beddard, with eyes that appear to be sightless, and A. oculatus, Beddard, with eyes that are pedunculate, though the stalks are unjointed, in these respects stand apart from the rest of the group. Arcturus longicornis, Haswell, supposed to come from Tasmania, has a preoccupied name, and the same author's Arcturus brevicornis, from Australia, appears to be awaiting closer identification.

The species referred or referable to Antarcturus appear to be the following: A. coppingeri, Miers, 1881, A. furcatus, Studer, 1884 (1882), A. glacialis, A. spinosus, A. anna, A. cornutus, A. spinifrons, A. purpureus, A. brunneus, A. abyssicola, A. myops, A. studeri, A. oculatus, A. americanus, A. stebbingi, all these thirteen instituted by Beddard in 1886, A. tenuispinis and A. multispinis, both established by Benedict in 1898, A. patagonicus and A. kophameli by Axel Ohlin in 1901, A. caribbæus, Richardson, 1901, A. oryx, zur Strassen, 1902, A. polaris, A. adareanus, and A. franklini, described by T. V. Hodgson in 1902, A. simplicissimus, A. dentatus, A. alcicornis, A. nodosus, A. serrulatus, published by Whitelegge in 1904, with A. kladophoros about to be described. To this formidable list should probably be added A. floridanus, Richardson, 1900, but, as this species was taken at Fernandina in Florida, above 30° North latitude, it far invades the zone which zur Strassen supposed to be devoid of Arcturi in the unrestricted sense of the term.

ANTARCTURUS KLADOPHOROS, n. sp.
Plate XXXII.

The species is not more spinose than several other members of the genus, some of which much surpass it in the length and strength of the spines they display. But none hitherto described have spines of the peculiar branching character here found, except A. alcicornis, Whitelegge, 1904, which, however, otherwise differs from the present species in several respects.

The head is squarely excavate in front, each of the lateral lobes carrying three or four small spines in advance of the dark red prominent facetted eyes, between which rise two simple and two multifid spines, while from the rear rise two long processes, blunt at the apex and branching into two spines and two blunt processes. The peræon segments increase in width to the third and in length to the fourth, this last being twice as long as the third, but tapering backwards.

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