288 Mr. H. J. Carter on hnown Fossil Sponges. 



to a copy of Prof. Scliulze's Report on the ' Challenger ' 

 dredgings of the Hexactinellida. 



Lastly, we come to my eighth order, viz. the Calcaeea ; 

 and here, again, we have to fall back upon the masterly re- 

 searciies of Professor Zittel, coupled with those of his intelli- 

 gent pupil Dr. G. J. Hinde — the former to be found in the 

 Abhandl. der bayer. Akad. W. ii. CI. xiii. Bd. ii. Abth., and 

 the latter in Dr. Hinde's ' Catalogue of the Fossil Sponges in 

 the British Museum,' p. 157 &c. Referring to Prof. Zittel's 

 observations on tlie " Occurrence, Distribution in Time, and 

 Pedigree " of the CalcispongitB (translation 'Annals,' 1879, 

 vol. iii. pp. 375-378), we learn, from the tabular view given 

 at p. 378, that, so far as is known, they at least date from the 

 Devonian period, are already numerous in tlie Triassic, increase 

 rapidly in the Jurassic, and cuhiiinate like the Lithistida in 

 the Cretaceous, after which isolated spicules only have been 

 found. 



At first (like all who attempt to generalize from insufficient 

 data) I was inclined to think, from the small delicate forms 

 and rapidly decomposing nature of the British species, that 

 it was impossible they could be subjected to the ordeal of 

 fossilization without disappearing altogether ; and if this had 

 been the case generally I might have been right ; but when I 

 found that Prof. Zittel had demonstrated the reverse, by 

 proving to me, from actual slices of what he considered to 

 be fossil calcareous sponges, that they possessed the peculiar 

 radiate spicules of a Calcisponge, and when, from the charac- 

 ters of the South-Australian sponges of the present day 

 which Mr. Bracebridge Wilson, of Geelong, kindly sent me 

 ('Annals,' 1886, vols. xvii. and xviii. p. 503 &c.), I could 

 acquiesce in this from recent specimens, the absurd notion 

 inferred from the characters of the British representatives of 

 this order could no longer be entertained. Meanwhile 

 several specimens from the Coral Rag (Jurassic system) of 

 Farringdon, in Berkshire, from which I made as many micro- 

 scopically thin slices, fully justified Prof. Zittel's announce- 

 ment. 



Furthermore, Dr. Hinde, in his " Notes on Fossil Calci- 

 spongice" ('Annals,' 1882, vol. x. p. 185, pis. ix. and x.), 

 describes not only specimens of his VerticilUtes df Orhignyiixova. 

 the Greensand at Warminster, in which the radiate spicules 

 could be seen with a simple lens in abundance on the surface, 

 but a new species of Sestrostomella from the Upper Greensand 

 of " Vaches Noires," near Havre, in France {S. rugosa, H.), 

 in which he found the " tuning-fork "-like form of spicule that 

 characterizes a recent species which Mr. Bracebridge Wilson 



