BIBLIOGRAPHY. 37 



structure agrees so closely with that of the existing family of Leucones, Hasck., 

 that they should properly be included in it. Further, regards the fibres of 

 these Sponges as not original structures but of secondary origin, produced 

 wholly by the process of fossilization. Refutes in detail the objections raised 

 by Steinmann to their spongeous nature, and fully confirms the previous results 

 of Zittel and Hinde. 



202. 1883 Carter, H. J. Further Observations on the so-called ' Farringdon 



Sponges ' (CalcispongitB, Zittel), followed by a description of an 

 existing species of a like kind (Ann. and Mag. Nat. Hist., S. 5, 

 vol. xi, pp. 20—37, PI. I). 

 Confirms the observations of Hinde on fossil calcisponges, and acknow- 

 ledges that they are rightly referred to this group. Thinks, however, that 

 Pharetrospongia Strahani, Sollas, and some species of Stellispongia, in which 

 only acerate spicules have been detected, cannot be claimed as calcisponges, 

 but that they are siliceous Sponges with their structures replaced by calcite. 

 Describes a recent form, Leucetta clathrata, in which the fibres are solid, as 

 in the Pharetrones. 



203. 1883 Caeter, H. J. Spicules of Spongilla in the Diluvium of the Altinuhl 



Valley, Bavaria (Ann. and Mag. Nat. Hist., S. 5, vol. xii, pp. 329 — 

 333, PI. XIV). 

 Detached spicules of the body-skeleton and of the gemmules are recog- 

 nised as belonging to Meyenia (Spongilla) erinacea, Ehr. 



204. 1883 Carter, H. J. On the Microscopic Structure of thin slices of Fossil 



Calcispongias (Ann. and Mag. Nat. Hist., S. 5, vol. xii, pp. 26 — 30). 

 Refers to projecting pin-like spicules on the surface of Vert ic ill ites anas- 

 tomosans, Mant., and to the changes in the fossilization of Pharetrones. 



205. 1883 Sollas, W. J. The Group Spongiaa (GasselVs Natural History, vol. vi, 



pp. 312—331, figures). 

 Refers nearly exclusively to recent Sponges and only the geological appear- 

 ance of the fossil forms mentioned. States that no fossil Sponge unquestion- 

 ably belonging to the Calcispongiee has, up to this time, been described. The 

 Monaxonidae, on the evidence of Cliona borings, are concluded to have been 

 in existence in early Palaeozoic times ; Pharetrospongia Strahani is said to be a 

 large Renierine Sponge, the best preserved and most certainly demonstrated 

 example yet known ; the Lithistidas are said to occur from the Upper 

 Cambrian to the Tertiary, and the Hexactinellidaa from the Lower Cambrian 

 upwards. 



