SPONGES. -HALLMANN. j j^-. 



Introductory Remarks. —The intimate relationship to one 

 another ot the sponges here regarded as varieties^ ot Rhaplii- 

 dophlus typicus, Carter, is revealed by their possession in com- 

 mon, of a considerable number of well-defined characteristics, 

 of which five may be considered as possessing special value.' 

 These are: — (i) The.non-occurrences of coring spicules in the 

 connecting fibres; (2) the reduction of spination in the sub- 

 basal region of the acanthostyles ; (3) the presence of two kinds 

 of chelae; (4) the torsion of the smaller chelae ;(5) the pecu- 

 liarities shown by the toxa. This assemblage of characters 

 distinguishes the sponges of the present seriesfrom any hither- 

 to described, 2 although it is only in their possession of 

 contort chelae of a special kind that they stand unique. It is 

 particularly on account of this last-mentioned peculiarity, 

 therefore, that their association under one specific name seem.s 

 advisable. The occurrence of two kinds of chelee is implied in 

 Wilson's description^ of Clathria {Tenacia] clatlirata, (O. 

 Schmidt), a species which is evidently very closely related to 

 the present, since it moreover possesses acanthostyles and toxa 

 of a similar kind. Clathria jugosa, Wilson, likewise, agrees 

 in regard to the latter two kinds of spicules. Acanthostyles 

 in which the spination is reduced over portion of their basal 

 moiety have also been described for R. ridleyi, Lindgren, and 

 R. filifer, R. and D., var. spinifera, Lindgren, although in R. 

 filifer itself the acanthostyles are said to be entirely spined. 

 The spicules of the t\pe-species of Rliaphidophlus, R. crati- 

 tius (Esper), described by Ehlers as "sehr feine haarformige 

 Kieselfaden welche ungleich lang und mannigfach gekrummt 

 sind" are almost undoubtedly identical in nature with the toxa 

 of R. typicus, and not sigmata as Ridley and Dendy have 

 suggested. 



Although the present species and R. paucispiuus differ 

 markedly in respect to their microscleres, yet, as regards their 

 megascleres they show a very close agreement. In R. typicus 

 we again find principal, auxiliary, and special dermal styli 

 occurring in the same relationships as described for the other, 

 whilst the acanthostyles, besides acting as echinating spicules, 

 are also similarly scattered within the fibres and through the 

 ground tissues. Further, the special dermal styli and, less 

 frequently, the auxiliary spicules, likewise exhibit a minute 

 spination and are similarly connected, the one kind with the 

 other, by a perfect series of intermediate forms. But whereas 



1 Hentschel (Fauna Siidvvest-Australiens, Bd. iii.. Lief. 10. 1911) has 

 recently described, under the name of Clathria typica, at least one other 

 variety. 



2 In speaking thus I assume that the descriptions of other species of 

 Bhujihidovhliitt are correct in detail. 



3 Wilson— Bull. U.S. Fish. Comm., xx. (1900). 1902. p. 397. 



