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

610 COLLECTIONS FROM THE WESTERN INDIAN OCEAN.Sarcode-spicules :—(3) Tricurvate acerate, smooth, tapering graduallyto fine points ; median curve rather sharp, forming angleof about 150° ; from this point arms almost straight, until justbefore tips, which turn up slightly ; size •19--22 by '006 millim.(4) Equianchorate, navicular, shaft slender, smooth, curve gradualand slight ;palms narrow, viz, about '08 long by '0055 millim. broad,tapering to sharp points at apex, square below ; tubercle slight,rather elongate, length -022 millim.Hah. Mozambique, between tide-marks.Two specimens and a fragment are in the coUeetion. The largestmeasures 110 millim. (4^ inches) in greatest height, 85 millim.(3^ inches) in greatest lateral expansion ; common stem 55 millim.long, 20 by 10 millim. in diameter at middle of its course, rathertortuous, deeply scored on one side by a main median longitudinaldepression. The second specimen has its branches more cylindricalthan those of the larger specimen : but it has grown abnormally, someof the branches being twisted back, and anastomosis occurs near thebase of the specimen. The description of Sponrjia palmata, Lamarck(Ann. Mus. Hist. Nat. xx. p. 453), var. /3, recalls this sponge. Thetypical form of the species, which I have seen at Paris, resembles itmore closely than does the specimen on which this var. /3 was probablyfounded ; however, microscopic examination shows S. ])ahnatato be a Chalina. While the present species resembles Desmacidonfruticosa, Mont., in texture and in the structure of the skeleton, itis yet quite distinct on account of its solid branches, its acerateskeleton- and its tricurvate (not bihamate) flesh-spicules. D.arciferum,Schmidt (Algiers), appears to approach it the most nearly ofdescribed species, but an acerate spicule is mentioned in addition tothe tricurvate. D. frondosum (Ehlers), Esper, from " East Indies,"resembles this sponge in general appearance, but has echinatingspicules, some of which are strongly spined, and no tricurvate ismentioned ; hence it seems to be a Clatliria.31. lotrochota purpurea.Halichondria purpurea, Boiverhanh, P. Z. S. 1875, p. 293.See Part I., p. 434, of this <strong>Report</strong>.Fine specimens, chiefly of the usual cylindrical form, and withthe same coarsely roughened surface as in the Australian specimens.Like those specimens, too, they show a tendency to become flattened,and to vary in colour from dark purple to dark green. The spiculationis essentially the same as in the Australian specimens. Themaximum height is also just the same, viz. 150 millim. (6 inches).Hah. Etoile Island, Amirante group, 13 fms.Distribution. See Part I. p. 434.32. lotrochota baculifera.See Part I., p. 435, of this <strong>Report</strong>.Some smaU specimens, in spirit and in the dry state. In the