20 BRITISH FOSSIL SPONGES. 



108. 1871 Geinitz, H. B. Die Seeschwamme des unteren Quaders. Die See- 



schwamme des mittleren und oberen Quaders (Palceontographica 

 Bd. xx, 1 Th., pp. 1—41, Pis. 1—10). 

 The identity of the minute structure of fossil Sponges with lattice-shaped 

 mesh (Gitterschwamme, A. Roemer) and recent hexactinellids is recognised, 

 and the fossil forms with this structure are placed in the same group with the 

 recent. Fossil Sponges with the so-called vermiculate mesh are regarded as 

 probably of the same nature as recent lithistid Sponges, and placed in the same 

 group. The doubtful Spongites is placed under the Halisarcina. The classi- 

 fication adopted by this author marks a great step in advance. A mistake 

 was made, however, in placing all Sponges with vermiculate fibres under the 

 Lithistidse, since many of them are calcisponges. 



109. 1871 Hicks, H. Descriptions of New Species of Fossils from the Longmynd 



Rocks of St. David's (Quart. Journ. Geol. Soc, vol. 27, p. 401, 

 PI. XVI, figs. 14—20). 

 Describes some doubtful lines on rock surfaces as Protospongia (?) major 

 and P. (?) flabella. 



110. 1871 Phillips, J. Geology of Oxford and of the valley of the Thames. 



Gives a list of the Amorphozoa of the Cretaceous system, and figures some 

 of the commoner Sponges from the Lower Greensand of Faringdon. 



111. 1871 Caeter, H. J. On Fossil Sponge Spicules of the Greensand compared 



with those of existing species (Ann. and Mag. Nat. Hist., 4 S., 



vol. vii, pp. 112—141, Pis. VII— X). 

 Very numerous forms of detached spicules from the Upper Greensand of 

 Blackdown and Haldon are shown to correspond very closely with the spicules 

 of recent tetractinellid, lithistid, and hexactinellid Sponges. 



112. 1871 Simonowitsch, S. Beitrage zur Kenntniss der Bryozoen des Essener 



Griinsandes (Verh. d. nat. Ver. Jahrg., xxviii, 3 Folge, Bd. viii). 

 Places as Bryozoa, Thalamopora cribrosa, Goldf., sp., and T. michelinii, n. 

 (pp. 27 — 34, PL 1, I, 2), now shown to be calcisponges and included in 

 Tremacystia, Hinde. 



113. 1872 Haeckel, E. Die Kalkschwamme. 



The author denies the existence of entire fossil calcisponges and states that 

 the forms generally known as such have no relation to the group. Further, 

 states that the delicate character of recent calcisponges renders it impossible 

 that similar forms can have been preserved in the fossil state, though it is 

 not improbable that their detached spicules may yet be recognised. 



