Geological Society, 479 



rilOCKEDlXGS OF LEARNED SOCIETIES. 

 GKOLOdlCAL SOCIKTY. 

 Xovomher 2l^ik1, 18'J9.— W. Whitakcr, li.A., F.R.S., 

 I'ri'sideiit, in the Chair. 



The following conimnnication was road : — 



' On some lleraarkablo Calcispongcs from the Eocene Tertiary 

 Strata of Victoria (Australia).' By (icorge Jennings Ilinde, Ph.D., 

 F.R.S., F.(J.S. 



The greater niunber of the sponges descril)e(l were discovered 

 by Mr. T. S. Hall, .M..\., of Melbourne University, in incoherent 

 detrital bods of Eocene age, in the southern i)art of Victoria ; a few 

 were picked out of some washings of fragniental polyzoa from 

 the same district and horizon, by Mr. B. W. Priest. Some of 

 the specimens are in an extremel}- perfect condition, and their 

 structural details are as distinctly shown as in recent sponges. 

 They are also of more than local interest in that they are the first 

 fossil forms described of a group of calcisponges, the Lithonina, 

 characterized by the peculiar aberrant forms of some of the spicules, 

 and the mode in which they are closely fitted and organically fused 

 together to form the skeletal mesh. This structure has, so far, only 

 been recognized in one recent species, FetroAtroina Schnlzei, Doderlein, 

 from the Japanese Sea. 



The sponges arc small, unattached, with a glassy, firm, resistant 

 skeleton, calling to mind that of siliceous Lithisfcida. They aro 

 built up of a great variety of sjicular forms, some are simple rods, 

 ■with three- and four-rayed spicules, similar to those in recent 

 calcisponges ; but the majority are aberrant four-rayed forms, with 

 three of the rays curved and with obtuse or expanded ends which 

 are clasped, and fused as %vell, to the surfaces of adjacent spicules. 

 The connected spicules form continuous anastomosing or radial 

 fibres resembling those in the fossil Pharetrones, to which they aro 

 in some other respects similar, and it is jjrobable that the spicules in 

 the fibres of some members of this family were likewise organically 

 cemented together. The common Forosphn'nv. from the Upper 

 Chalk, generally regarded as Hydrocorallines allied to the recent 

 MUlepora, are also closely related to the above sponges, and the 

 Author ho[tes shortly to publish the evidence for their afl^inity 

 to this grouj). 



The Victorian sponges are- placed in four new species, belonging 

 to three genera : two of these are new, the other, Bactronella, Hinde, 

 •was founded on some peculiar calcisponges of Jurassic Age, now 

 known to 1)0 Lithonine in character. 



December 6th, 1899.— W. Whitaker, B.A., F.R.S., 

 President, in the Chair. 

 The following communication was read: — 



'On the Geology and Fossil ('orals and Echinids of Somali- 

 land.' By Pr. J. W. (Jr. gory, F.G.S. 



British Somaliland consists of a high plateau, of which the 

 northern scarp is separated from the Gulf of .Vden by a belt of low 

 hills and plains known as the Guban. The southern plateau 



