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Show 112 ZOOLOGICAL COLLECTIONS MADE DURING [Jan. 4, Pores. The dermis is not sufficiently well preserved to show them. Hab. Portland Bay, Chili (in the channel between the chief island of the Madre-de-Dios archipelago and the mainland), 10 fathoms. Obs. The nearest identifiable ally of this Sponge appears to be that described by Schmidt1 as Siphonochalina bullata, which, as already observed, it probably resembled closely in external characters. It is not certain that that Sponge is identical with the Callyspongia bullata of Duchassaing de Fontbressin and Michelotti; and it certainly is not the Spongia bullata of Lamarck, which those authors consider their Sponge to be. The chief distinguishing characters of the two Sponges are as follows: - Siphonochalina fortis (Chili). External Characters. /Form tubular, perhaps rising from an enlarged base. (Several tubes rising S. bullata, Schmidt | from one base. (?Duch. et Mich.,non J Lamk.), (West In-'1 dies). Main Skeleton. Network open. Two sets of fibres regularly arranged at right angles; fibres from '07 to "25 m m . in diameter. Network close. Two sets of fibres regularly arranged at right angles; fibres from -0355 to "1065 m m . in diameter. Spicules. Acerate, tapering abruptly. Size -07284 by -0079 millim. Acerate, tapering abruptly, size '076 by •025337. C L A D O C H A L I N A A R M I G E R A , Schmidt (nou Duch. de Fontbressin et Michelotti), var. P E R G A M E N T A C E A , nov. (Plate X. fig. 4.) Cladochalina armigera, O. Schmidt, Spong. atl. Geb. p. 35. A fine dried specimen appears to represent this species, although it shows some important differences from it. External Characters. Suberect, elongated, flattened from side to side, the long diameter being about three times as great as the short diameter; the upper of the two edges bears most of the vents. It is curiously bent to form an angle of 60° at about its middle, so that the apex nearly touches the rock on which it stands. Surface even except near the vents, and smooth, though finely striated by a sub-dermal and a dermal network of coarser and finer fibres respectively. Colour pale brown. Vents subcircular, long diameter from 1 '5 to 3 millims., occurring at intervals of 8 to 15 millims. along the edges of the Sponge ; they stand out on small rounded eminences to a height of about 1 millim. from the surface, and end in a reticulated bottom at from 2 to 4 millims. below the edge. Pores 1 Main Skeleton. Composed of a vertical (" deep ") set of strong horny fibres, of '04434 millim. average diameter, coming from the centre, giving off numerous smaller branches laterally, and meeting at right angles a stout (" subdermal ") set of fibres, diameter '056 to '14 millim., which run along parallel with the surface, branching and anastomosing so as to form the coarser meshes of the surface, and have a tetra- to polygonal outline. Thesubdermal network forms 1 Spong. atl. Geb. p. 33. |