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

604 COLLECTIONS FROM THE WESTERN INDIAN OCEAN.skeleton— primary fibres vertical to surface, about a spicule's lengthapart, containing 3 to 5 series of spicules ; secondaries at varioiisangles to primaries, spicules 1- or 2-serial. Sarcode rich brown,subtransparent. Spicules acerate, slightly curved, tapering to sharppoints from about 3 diameters from ends ; size -17 by '0085 millim.It branches once at an angle of about 35°, its total length is 50millim. (2 inches), and it has involved a mass of Polytrema, Nullipore,cfec, in its course ; the Nullipore bears the specimen which Ihave provisionally assigned to Chondrilla mixta, Schulze.In the character of the skeleton and the size of the spicules thisspecies resembles the British species IsocUctya simulans, Bowcrbank,and Chcdina montar/ui, Johnston ; but it has not the firm texture ofthe former, nor the tubular form of the latter, and I have not foundany more nearly allied species. In spite of its repent growth I haveassigned it to Clialina rather than to CladochaUna, the proportionsof the spicules and the character of the fibre agreeing with thoseof typical Ghalince (GhaUmda of Schmidt), and being in my viewfar superior as diagnostic characters to those taken only from theexternal habit.Hab. Marie Louise Island, Amirante group, 16-17 fms.ACERVOCHALINA, gen. n.See Part I., p. 398, of this <strong>Report</strong>.21. Acervochalina finitima, var.Ohalina finitima, Schmidt, Sponr/. Atl. Geb. p. 33.As on the North- Australianmargin of the Indian Ocean, so alsoin its North-western angle this otherwise West-Indian* speciesseems at home. Two specimens (the one 25 millim., the other 40millim. in extreme diameter) show the essential characters of thespecies ; the vents, however, unlike those of the Australian specimens,are placed on the margins rather than the upper surface ofthe sponge, and the spicules are slightly thicker than in both the Australianand W. -Indian forms, viz. '003 millim. as against '0018 inthe one and -0025 in the other.Bed). Seychelle Islands, 4-12 fms.Distributioti. See Part I., p. 399, of this <strong>Report</strong>.RENIERIDtE.Besides the probably almost cosmopolitan species Tedania digitata,I find that several of the representatives of this generalizedFamily type have quite a European fades, and I have identified twoof them {Beniera indistincta and rosea) with British species ; buttwo members of the same genus, now described for the first time,possess external characters of a definiteness and singularity unusual* Also British, if Chalina limhata, Bowerbank, is identified with it.