472 COLLECTIONS FROM MELANESIA. 



4. S. crassicula, id. ibid. p. 371. Basse Rocks, Ceylon. 



5. S. australiensis, 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 bacillar or acerate flesli-spicule. 



7. S. tethyopsis, Carter, Ann. & Mag. INT. H. 1880, v. p. 137, pi. 

 vi. figs. 39, 40. Gulf of Manaar, Ceylon. 



8. S. globostellata, id. op. cit. 1883, xi. p. 353, pi. xiv. fig. 5. 

 Galle, Ceylon. 



9. S. bacca, Selenka, Zeitsch. wiss. Zool. xvii. p. 569, pi. xxrv. 

 figs. 14, 15. Samoa Islands. 



10. S. purpurea, sp. n. N. coast of Australia. 



11. S. clavosa, sp. n. JS". coast of Australia*. 



In no Atlantic Stelletta; which I have seen do the minute or any 

 stellates possess capitate rays, except in a MS. species of Schmidt's 

 from Florida, which has minute drawn-out stellates (i. e. incipient 

 spinispirular spicules) with very slight heads to the slender rays ; a 

 larger stellate is, however, present in addition to these, and has not 

 heads to its rays ; the large stellate of S. intermedia, Schmidt, 

 from Algiers, has the ends of the rays roughly tuberculated by pro- 

 minent groups of tubercles, but the spicule itself seems to be homo- 

 logous with the " balls " of Geodia, and not with the small stars of 

 Stelletta, which are present as well. The Indo-Pacific species more 

 often have the head. In Stelletta (Ecionemia) densa, Bowk., from 

 the Fiji Islands, the tuberculation of the rays is sometimes rather 

 coarser at their apices than on the remaining part, and in Ecionemia 

 acervus the rays of the delicate stellate are very fine and slightly 

 capitate. Carter does not describe or figure any heads on the rays 

 of the stellates of his species from this region excepts, globostellata. 

 Selenka's species has no heads. 



The two species from Australia to be first described agree with 

 each other and with Ecionemia acervus in having small heads to the 

 stellates, although they differ from it, and agree with Stelletta tethy- 

 opsis, in the probably more important character of the absence of 

 a flesh acerate or bacillar spicule ; the character of the apex of 

 the ray of the stellate in the latter species has not been described. 

 The Samoa-Islands species has no surface linear spicule assigned to 

 it by its describer, but it differs fundamentally from our species in 

 its large, noncapitate-rayed stellate. 



* S. euaafrtim of Carter (? Schmidt) described (Ann. & Mag. 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 from 

 Schmidt's species ; they belong to a remarkable group of forms which connect 

 Stelletta with Geodia : the surface-disk forms a character of sufficient import- 

 ance to distinguish the species which possess it from Stelletta s. str. S. ni'.v of 

 Selenka (Zeitsch. wiss. Zool. xyii. p. 569, pi. xxxv. figs. 11-13), from the Samoa 

 Islands, is probably a Tethya s. str., as its stellate agrees with the large stellate 

 of that genus, and its " forks " are rare and probably foreign to the sponge. 



