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

472 COLLECTIONS FROM MELANESIA.4. S. crassicula, id. ibid. p. 371. Basse Eocks, Ceylon.5. S. aiistraliensis, id. op. cit. 1883, xi. p. 350, pi. xiv. fig. 2.W. Australia.6. S. bacillifera, var. robusta, id. loc. cit. p. 351, pi. xiv. fig. 3,S. Australia.Group 2.Without baciUar or acerate flesh-spicule.7. S. tethyopsis, Carter, Ann. & Mag. N. H, 1880, v. p. 137, pi.vi. figs. 39, 40. Gulf of Manaar, Ceylon.8. S. glohostellata, id. op. cit. 1883, xi. p. 353, pi. xiv. fig. 5.Galle, Ceylon.9. S. hacca, Selenka, Zeitsch. wiss. Zool. xvii. p. 569, pi. xxxv.figs. 14, 15. Samoa Islands.10. S. purpurea, sp. n. N. coast of Australia.11. S. clavosa, sp. n. N. coast of Australia*.In no Atlantic Stellettce which I have seen do the minute or anystellates possess capitate rays, except in a MS. species of Schmidt'sfrom Florida, which has minute drawn-out stellates (i. e. incipientspinispirular spicules) with very slight heads to the slender rays ; alarger stellate is, however, present in addition to these, and has notheads to its rays ; the large stellate of S. intermedia, Schmidt,from Algiers, has the ends of the rays roughly tuberculated by prominentgroups of tubercles, but the spicule itself seems to be homologouswith the " balls " of Geodia, and not with the small stars ofStelletfa, which are present as well. The Indo-Pacific species moreoften have the head. In Stelletta (Ecionemia) densa, Bowk., fromthe Fiji Islands, the tuberculation of the rays is sometimes rathercoarser at their apices than on the remaining part, and in Ecionemiaacervus the rays of the delicate stellate are very fine and slightlycapitate. Carter does not describe or figure any heads on the raysof the stellates of his species from this region exee])t S. glohostellata.Selenka's species has no heads.The two species from Australia to be first described agree witheach other and with Ecionemia acervus in having small heads to thestellates, although they differ from it, and agree with Stelletta tethyopsis,in the probably more important character of the absence ofa flesh acerate or bacillar spicule ; the character of the apex ofthe ray of the stellate in the latter species has not been described.The Samoa-Islands species has no surface linear spicule assigned toit by its describer, but it differs fundamentally from our species inits large, noncapitate-rayed stellate.* S. euasifrum of Carter (? Schmidt) described (Ann. & Mcag. Nat. Hist. 1882,V. pp. 135, 13G, pi. vii. figs. 41, 42) from the Gulf of Manaar and Australia,includes two distinct species, of which the first at any rate is distinct fromSchmidt's species ; they belong to a remarkable group of forms which connectStelletta with Geodia : the surface-disk forms a character of sufficient importanceto distinguish the species which possess it from Stelletta s. str. S. nvx of11-13), from the S.amoaSelenka (Zeitsch. wiss. Zool. xvii. p. 569, pi. xxxv. figs.Islands, is probably a Tethya s. str., as its stellate agrees with the large stellateof that genus, and its " forks " are rare and probably foreign to the sponge.