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Show 128 ZOOLOGICAL COLLECTIONS MADE DURING [Jan. 4, surface, the openings being those of the excretory canals. Main skeleton of spiculo-fibre, the spicules united by a minimum of sarcode, consisting of a primarv set of fibres, from 6 to 10 spicules thick, at right angles to the surface, from which they project (multiplying as they approach the surface by branching), connected by a secondary set at right angles to them, containing usually from three to four spicules in their diameter, and by an irregular network of single spicules or bispicular fibre, crossing the interspaces at various angles. Dermal Skeleton. An irregular reticulation, 1 to 6 spicules thick, lying between the points of the primary-skeleton fibres in superficial pigmented layer. Parenchyma semiopaque, muddy-brown in colour. Spicules-but one form for all parts, viz. a smooth acerate, slightly bent at the middle, ending rather gradually ; size '17736 by "00887 millim. Embryos, apparently in the planula stage, lie embedded near the interior surface of the Sponge ; they are oval; the greatest diameter varies from '24 to "43 millim. In one place a dense mass of about 15 occurred. As the specimen was taken on March 3rd, 1879, the sexual period is hereby fixed. Examined. In spirit, and by mounting in balsam. Hab. Trinidad Channel, Chili (just north of chief island of Madre-de- Dios archipelago), 30 fathoms. Obs. The specimen differs somewhat from the original specimens of the species, though hardly enough for it to form a new species. The chief differences are here tabulated :- External Characters. S. aulopor a, West Indian specimens •{ {Schmidt). /'Massive, sub-erect ; vents along edge of column, in distinct tubes. Yellowish in \ dry state. /Massive; vents on distinct tube or tubes. Didl S. aulopor a, var., •{ brown in spirit. S.W. Chili. Skeleton. Primary1 lines project slightly from surface; spicules 6- to 12-serial in them; secondary lines 5- to 7-serial. Primary lines project considerably from surface; spicules 6- to 10- serial; secondary lines 3- to 9- serial, Spicides. Acerate, slightly bent at middle, tapering slowly'off to points. Size •165 by -00792 mm. As in preceding. Size -17736 by •00887 m m . The probable type specimen of Lsodictya mirabilis, Bowerbank, from the " East Indies," has spicules measuring "1771 by "0079 millim., and agrees well (apart from the presence of the polyp-cells) with Schmidt's species in external characters, although the tendency of the vents to become elevated on separate tubes towards the base is but slightly marked. If the locality for that species is correct, the distribution is a very wide one-assuming the identity of the 1 It should be noted that the specimen from which the character was taken was probably dried before being mounted; therefore the ends of the fibres had probably been rubbed. |