so-called 1 ' Far ring don Sponges" 21 



the specimens and preparations from which they were com- 

 piled, whereby I have been able to confirm all that lie has 

 stated respecting them. Not only this, but in a slice of a 

 specimen of Verticillites (Defr.) anastomans, Mant., from Far- 

 ringdon, in my own cabinet, I see similar spicular structure to 

 that which Dr. Hinde has represented in his V. D' Orhignyi) 

 as also in one from a specimen of Sestrostomella (Jura), 

 which Prof. Zittel kindly sent me, in which the pitchfork-like 

 (two-pronged) spicules of Dr. Hinde's two SestrostoineUm are 

 also present, and have been identified, as he has identified them 

 ' before, with the representations of the existing calcispicules to 



which the late Dr. Bowerbank gave the name of " inequi-fur- 

 cato-triradiate " (No. 1, vol. i. p. 268, pi. x. fig. 237), sub- 

 sequently found by Hiickel in Calcisponges from the coast 

 of South Australia and the Indian Ocean (No. 2, Atlas, 

 Taf. xxiii. fig. h y and vol. ii. pp. 127 and 166). Hence 

 there can no longer be any doubt, with this additional know- 

 ledge, that there are, in Prof. Zittel's order of fossil Calci- 

 spongise, at least some genera w r hose fibre bears spicular forms 

 which are identifiable with those of existing Calcispongige. 

 Further than this, in the prepared slice of Peronella multi- 

 digttataj Mich., kindly sent me for conviction by Prof. Zittel, 

 not only are the triradiates identical, as I have before stated, 

 but their peculiar arrangement I now see, in one part at least, 

 is equally identical, with that of existing Calcispongias. 



Still, although the spiculation in many instances, especially 

 in that problematical form Verticillites, may so far aid us in 

 identifying these fossils with the Calcisponges of the present 

 day, there are others in which it appears to be of so little ser- 

 vice in this respect that, if these are also to be regarded as 

 I Calcisponges, they must also be considered extinct, so far as 



our knowledge of existing forms go ; for there is no Calcisponge 

 of the present day with which such spiculation can be directly 

 identified. 



Thus in Manon macropora, Sharpe,= Elasmostoma 7 From. 

 (No. 8, vol. iv. p. 130), Prof. Sollas, who has examined 

 its fibre microscopically in the usual way (that is, by ex- 

 tremely thin slices mounted in Canada balsam and viewed 

 by transmitted light through the microscope), has noticed and 

 delineated slender thread-like forms, triradiates, quadi intdiates, 

 and even quinqueradiates, together with bifurcated arms and 

 truncated shafts or branches (No. 9, vol. iii. p. 354, pi. xiv. 

 tigs. 2, 5, 14, 7, 11, 12, and 19 respectively), the slender 

 thread-like forms, or " filiform spicules," as they are after- 

 wards termed, chiefly occupying the outer part of the fibre, 

 and the " multiradiates " the axis ; also that while " in some 





