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

016 COLLECTIONS FROM THE WESTERN INDIAN OCEAN.mentioned by Carter, II. cc.) of a fine tricurvate acerate flesh-spiculein addition to an equianchorate. A third species, E. vasipliccda.,assigned by Carter {op. at. 1882, x. p. 114) to the genus belongs,as I have stated in my report on the Australian collections (Part I.p. 454), not to this genus, but to EcMnodictyum, mihi. The genuswas not met with by the ' Alert ' on the north and east of Australia,although it is common on the south and south-west (Carter) ;it isa little strange therefore to find the following two species in thewestern part of the Indian Ocean.38. Echinonema, sp.A small, irregularly-grown specimen in spirit, consisting of anextended coating base and three low lobes, more or less flattened,,two of them uniting with each other. Surface corrugated by lowmseandering ridges, giving an irregularly dimpled aspect to the surface; dermal membrane upon the ridges glabrous. Vents small,scattered, oval or circular, "6 to 1*0 millim. in diameter, generallyplaced on margins or in depressions rather than in the middle ofsurfaces. Consistence in spirit firm, very tough, elastic ; colour duUumber-brown.Main skeleton approximately rectangular in arrangement, the primaryfibres being set vertically to the surface, and the secondariesparallel to it, but with their ends curved round to meet the primaries ;fibre very strong, pale to dark amber-yellow in colour : the primaryfibres about "14 millim. thick, and cored for one to two thirds of theirthickness by subspinulate spicules ; secondary fibre "07 to "14 millim.thick, either devoid of spicules or cored by at most two series.Dermal skeleton formed by a set of radiating tufts of subspinulatespicules, the bases of the tufts being placed about '25 millim. apart,and the ends of the spicules of the different tufts intercrossing. 8arcodepale yellowish brown, subtransparent. Spicules :— (1) Skeletaland dermal subspinulate ; head slight, oval, provided with a fewvery fine terminal spines ; head of about the same diameter as middleof shaft; tapering gradually to sharp point; size '26 by -008 millim.(2) Echinating spiued subspinulate ; the head and distal two thirdswell spined ; spines strong, sharp, projecting at right angles tosurface ; size of spicule -1 by '0085 millim. (3) Tricurvate acerateof sarcode, median curve rather sharp ; size "04 by '001 millim.(4) Equianchorate, navicular, shaft slightly curved ; length of spicule•012 millim.Hah. Etoile Island, Amirante group, 13 fms. ; attached to deadcoral.This species is evidently nearly related to E. typicimi and E. ancJioratumof Carter, from its resemblance in external form and inspiculation. The structure of the dermal " crust " is essentially thesame as that described by me in the nearly allied genus JRhaphiflopMus(see R. arborescens and B. procerus, Part I. pp. 450-1, ofthis <strong>Report</strong>).