Mr. H. J. Carter on known Fossil Sponges. 289 



sent me from the neighbourhood of Port Phillip on the south 

 coast of Australia, first represented by Dr. Bowerbank 

 (B. S. vol. i. fig. 237) and subsequently called '■'•Lelap'ia 

 australis'' by Dr. Gray (Proc. Zool. Soc. 1867, p. 557). I 

 have said " species " because the upper part of the specimens 

 which Mr. Bracebridge Wilson sent me (' Annals,' 1886, 

 vol. xviii. p. 148) bore a close resemblance to the heads of 

 Sestrostomella represented by Dr. Hinde, as well as ti^ those 

 of a fossil group from the Jura which Prof. Zittel kindly sent 

 me, in which, in microscopic slices, I also found the form of 

 spicule mentioned ; all of which demonstrates the accuracy 

 of Prof. Zittel's observations. 



I wish also to note here that, although I have considered 

 Dr. Sollas's " Pharetrospongia Strahani " (Quart. Journ. 

 Geol. Soc. May 1877, p. 242), from which Professor Zittel 

 has taken the name of his third family of this order, viz. 

 " Pharetrones," among his Calcispongia^ (' Handbuch,' p. 189), 

 to be a siliceous sponge like an Australian species of Reniera 

 (Monaxonia) whose spicule Dr. SoUas has introduced among 

 his illustrations for comparison {op. et lac. cit. pi. xi. figs. 11 

 and 12), yet from subsequent facts which have come to my 

 knowledge, — such as the existence of a Calcisponge with the same 

 kind of fusiform, sharp-pointed, acerate spicule, viz. Leucyssa 

 spongilJa^ Hack. (' Die Kalkschwiimme,' Bd. ii. p. 137, Atlas, 

 Taf. XXV. figs. 11-13), evidently designated after the character- 

 istic spicule of Sjjoyigilla (although it should be also stated that 

 the spicule of Leucyssa spongilla is not curved as in Spongilla 

 and Pharetrospongia Strahani^ &c., but straight, still it is the 

 only form of spicule in this sponge), — together with the state- 

 ments of Dr. Hinde (Cat. Foss. Sp. B. M. pp. 202, 203) in 

 support of Prof. Zittel's view that Pliaretrospongia Strahani 

 was a Calcisponge, I must now yield to their opinion, who 

 for a while made the study of fossil sponges their special 

 object. 



Thus, in conclusion, I have given a short sketch of the 

 known history of sponges in time and space from the earliest 

 geological periods up to the present day, among which we 

 notice the absence of any fossil representative of the Horny 

 Sponges, which are now so abundant and whose fibre in many 

 instances (ex. gr. Luffaria) is almost entirely composed of 

 spongin, which, in elementary composition, as shown in the 

 first part of this paper^ only difi'ers from chitin (the elytra 

 of insects) in quantity, while the quality of resistance would 

 appear to be in favour of the former; and yet fossilized 

 insects have been handed down to us in almost every geolo- 

 Ann. & Mag. N. Hist. Ser. 6. Vol. iv. 20 



