Report on the zoological collections made in the Indo-Pacific Ocean ...

ECHINODERMATA. 159syzj-gy. Ten arms. First brachials wider without than williin, incontact, with a convex median protuberance along their distal edge ;the second with sides a little more regular ; the third almost square,a syzygy. The fourth to seventh joints a little wider than long;eighth or ninth a syzygy. The succeeding joints wedge-shaped,with their free margins a little overlapping and slightly toothed.About 5-8 joints between the succeeding syzygies.The earlier pinnules are extraordinarily stiff; the first, which ison the second brachial, is much shorter than the second or third,which are of about the same length and made up of rather less than20 joints, most of which are longer than wide, and have their distaledge enlarged and slightly denticulated. There are 10 or }2 stiffpinnules ; the succeeding ones are shorter, and then again longer.Arras more than 120 millim. long ; disk not more than 7 millim.in diameter. The radials and the earlier brachials have theirinfero-lateral edge produced into a kind of ledge. The moreproximal joints have the appearance of being tuberculated, andthere is a taint median dorsal ridge ; at the sides they are compressed.Colour dark slate.The stiff pinnules, the long arms, and the small disk are verystriking characters in this species.Port Denison.The large Myzostomum found on it has been named M. coriaceumby Dr. Graff.8. Antedon decipiens. (Plate XI. figs. B, a.)Centrodorsal small ; drri on three levels, about 20 in number,with 25 joints, of which the fourth to tenth are longer than wide ;the rest, which gradually become shorter, are provided with a wellmarkedspine ; these decrease towards the end, but the penultimateone is larger again.First radials quite distinct ; the second oblong, three times aslong as wide, partly in contact ; the third almost triangular. Thearms may or may not divide, so that there are from about 14 to 18.The first brachials or first distichals are always wide, and touch ;where the arms divide there are three distichals, and the axillarymay be a syzygy. The first brachials, which have sharp overlappingdistal edges, are pretty regularly oblong ; at about the seventh theybecome alternately wider on either side, to again become moreregular later on.Syzygies 3, 12-15, 22-25; then from ] 0-12 joints between eachsyzygy.First pinnule on second distichal (when present), that and theone on the third brachial short ; those on fifth to ninth much lon"-erthe basal joints very stout, the free ends very delicate, and theirouter side produced into a well-marked conicfti process. The succeedingpinnules are shorter, and these again increase in length •they are not composed of a large number of joiuts.