22 THE VOYAGE OF H.M.S. CHALLENGER. 



and Vosmaer, thougli inclined to place it systematically near Aplysilla, do so with great 

 reserve, " provided that its internal organisation does not differ from that of other 

 Aplysillidse." I am in a position to authorise this proceeding entirely. Some time after 

 having published his paper on this form, Prof. Schulze visited a Dalmatian Island, Lesina, 

 and there dredged up specimens of a sponge which does not admit of even a specific 

 distinction from Darivinella aurea, Fritz Miiller. Prof. Schulze has been kind enough to 

 hand me over these specimens for examination, and I can state that the internal organisa- 

 tion of Darivinella aurea follows on the whole the type, anatomical as well as histological, 

 characteristic of Aplysilla. Accordingly, and in opposition to Dr. Vosmaer,^ since the 

 family name of Darwinellidae was established by Merejkowsky ^ in the year 1878, that 

 of Aplysillin^, v. Lendenfeld' and Aplysillidas, Vosmaer,^ only in the year, 1883, 

 I propose to return to the former name of the family in question. The genus Darwinclla 

 is a good one, its horny spicules differentiating it sharply from all other Keratosa. 



A'plysilla, F. E. Schulze^ {Simplicella, Merejkowsky "). 



Lendenfeld' characterises this genus by its crust-like form and by numerous inde- 

 pendent tree-like skeletal fibres, — a character common also to Darivinella. The 

 distinction consists in the absence of spicules. This genus would be a good one only 

 if united with the next under consideration. 



Dench'illa. 



Here v. Lendenfeld® finds the generic character in the property that the skeletal 

 fibres do not stand separately as in Aplysilla, the whole skeleton presenting a single 

 tree with numerous secondary, tertiary, and other branches. This distinction is, how- 

 ever, scarcely of generic consequence. In the Spongelidse F. E. Schulze " has 

 described a form [Spongelia S2nnifera), which differs from other representatives 

 of the genus in the same direction, but even more than Dendrilla from A2Jlysilla; 

 yet he merely placed it as a new species in his genus Spongelia. At any rate Ap)lysilla 

 and Dendrilla show much closer affinities with one another than with Darwinella or 

 lanthella. 



lanthella. 



This genus was established in the year 1869 by Gray,'" as the representative of an 

 independent family of horny sponges, and excited among naturalists a great doubt 



' On Velinea gracilis, p. 444. ^ jVfg,^ j^, I' Acad. d. Sci. de St. P^tersb., tome ,\xvi., No. 7, p. 44. 



3 Zcitschr. f. wiss. Zool., Bel. xxxviii. p. 235. i Loc. cit., p. 44.3. 



5 Zeitschr.f. vdss. Zool., Bd. xxx. p. 404. « Loc. cit., p. 43. ' Loc. cit, p. 309. 



8 Ibid., p. 270. " Zeitschr.f. wiss. Zool, Bd. xsxii. p. 152. i" Proc. Zool. $oc. Lond., 1869, p. 49. 



