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



stated, from a theoretical point of view it appears to be but of a subordinate character, 

 the possibility is not excluded that the property in question might have been assumed 

 very early (in a pala3ontological sense), and thus if we should in time find lanthellidse, i.e., 

 horny sponges whose skeletal fibres are charged with true cells, of thoroughly different 

 internal organisation, we should be obliged to elevate the character in question to the rank 

 of that of a subfamily or even family. But hitherto this has not been the case ; all the lan- 

 thellidge known up to this time are only representatives of the same genus, and in order 

 to avoid a superfluous overburdening of spongiological nomenclature, sufiiciently overbur- 

 dened already. I should propose to regard temporarily the genus lanthella as merely a 

 genus of the family Darwinellidse (Aplysillidte), the more so as to a similar variation 

 (in the reverse direction, however,) in the Vertebrata^ no systematic consequence has been 

 ascribed. 



This would be the place to discuss the systematic value of the organisms known by 

 the name of " Fibrillen " or " filaments," which for a long time have been considered a 

 constituent part of the horny skeleton. The inducement to this has been given by the 

 statements of Oscar Schmidt, who thought ^ he had seen filaments in immediate connec- 

 tion with true horny fibres. On the ground of this false supposition he adopted the 

 genus Hircinia, Nardo, and characterising it primarily by the presence of filaments, 

 subdivided it into two subgenera; Gray'* in the year 1867, relying on Oscar Schmidt's 

 statements, established a new family " Hircinidse," characterised by the possession of a, 

 so to speak, double skeleton. There has been however, on the part of other spongio- 

 logists, some doubt as to the reliability of Schmidt's statements. KoUiker* proclaimed 

 the filaments to be parasites, and this opinion has been warmly defended also by Mr. 

 Carter,' apart from the point that, according to Kolliker, the filaments are fungi, accord- 

 ing to Carter, algfe. In the meantime, Prof. Schmidt" altered his opinion ; further and 

 more careful examination led him to the conclusion that the filaments were in no 

 connection with the true skeleton, and this suggestion has been confirmed also bj^ 

 Schulze in his paper on " die Gattung Hircinia, Nardo und Oligoceras, g. n." Agreeing so 

 far as the real facts are concerned, both the investigators just named difier, however, with 

 regard to further conclusions. In his report on the Spongien der Kiiste von Algier 

 Prof. Schmidt believes^ that if it were once proved that the filaments are nothing but 

 parasites, the genus Hircinia ought to be dissolved as an independent genus, and incor- 

 porated in the genus Cacospongia. Prof. Schulze comes to quite a different conclusion ; 

 while inclined, as he has been, to regard the filaments as independent organisms, he 

 ascribes* to their presence in certain Keratosa a generic and even family character, which 



1 I allude to the osteoblastless skin-bones of Cceciliae (Leydig) as well as to the equally osteoblastless bones of 

 Teleostei supporting their fins (Kolliker). 



2 Spong. d. Adriat. Meeres, pi. iii. fig. 10. 3 p^gg^ Zool. Soc. Land., 1867, p. 503. 



* Icones histologicce, Abth. i. p. 49. ^ Ann. and Mag. Nat. Hist., ser. 4, vol. viii. p. 330, 



^ Zeitschr. f. v:iss. Zool., Bd. x.xxi. p. 661. ' 1871. 



' Zeitschr. f. vnss. ZooL, Bd. xxxiii. p. 34. ^ Loc. cit., p. 36. 



