AKT. 12 HEXACTINELLID SPONGES — OK ADA 61 



it differs in some respects from the type, I am strongly inclined to 

 refer it to G. spinifera. It comes from Sagami Bay (Station 5085), 

 where it ATas taken at a depth of 622 fathoms. 



Although the sponge has come to maturity, I have, unfortunately, 

 not found the spines on the paratangentials of the dermal oxypentac- 

 tins, which constitute a characteristic feature of the species. As to 

 the forms or varieties of discohexasters, I have also met with nearly 

 the same forms as those occurring in the type specimens, but their 

 dimensions seem to be different from those of the latter. Of the 

 discohexasters, the comm.onest form, corresponding in outer appear- 

 ance to that which Ijima (loc. cit. p. 76) called the first variety 

 in the typical species, has somewhat larger dimensions, attaining 108/x, 

 in diameter. The second variety (loc cit. p. 75) in the typical species 

 often apjoears and varies from 120/i to 180/a in diameter. In outer 

 appearance it is to be considered as represented by two forms. One 

 has a widely expanding bunch of terminals and is 160/x to 180/x in 

 diameter, while the other forms somewhat slender terminals, grouped 

 separately, narrow at the middle and outwardly expanding into tufts, 

 usually measuring 140/x in diameter. The largest variety, which 

 Ijima called form c in the type specimens, appears occasionally. Its 

 diameter falls short of the 230//, of the type specimens, measuring 

 only 210/j, in the present specimen. The fourth variety of disco- 

 hexaster seems to be wanting here, but perhaps it is to be considered 

 as represented by the much more delicate form that I have just 

 mentioned above in the case of the second variety. The discohex- 

 asters thus far indicated have specific features somewhat different 

 from those of the t^^pe specimens. I identify the present specimen as 

 ChaunoplecteUa spinifera^ regarding the spicular differences to be a 

 matter of individual variation. 



Family EUPLECTELLIDAE (Gray) Ijima, 1903 

 Subfamily EuPLECTELLiNAE Ijima, 1903 



Genus EUPLECTELLA Ijima, 1903 



EUPLECTELLA OWENI Kerklots and Marshall 



Euplectella M. J. S. Schtjltze, Eiu Beitrag zur Naturgeschiclite der Spongiea, 

 Bonn, p. 39, 1860. 



Euplectella oweni Kerklots and Marshall, Arch. N^erland. Sci. Exact, et Nat., 

 vol. 3, p. 435, 1868. — Makshall, Zeit. Wiss. Zool., vol. 25, suppl., p. 189, 

 figs, in pis., 1875; vol. 27, p. 128, 1876. — F, E. Schulzb, Abh. kou. preuss. 

 Akad. Wiss. Berlin, 1886, p. 38; Rep. Voy. Challenger, vol. 21, p. 78, pi. 6, 

 figs. 1, 2, 1887; Alih. kon. preuss. Akad. Wiss. Berlin, 1895, pp. 29, 48.— 

 Ijima, Journ. Coll. Sci. Imp. Univ. Tokyo, vol. 15, p. 202, pi. 6, figs. 1-10, 

 1901. 



There are five specimens of E. oweni in the collection, which were 

 taken as indicated in Table 16. 



