180 Geological Society. 



November 25, 1891.— Sir Archibald Geikie, D.Sc, LL.D., F.R.S., 

 President, in the Chair. 



The following communication was read : — 



" On tlie Os pubis of Polacanthiis Foxi." By Prof. H. G. Seelev, 

 F.R.S., F.G.S. 



Hitherto the eridence of the systematic position of Polacanthns 

 has not been very precise. The Author lias detected the raissin<>: 

 pubis as an isolated specimen, lliis he regards as the anterior por- 

 tioti of the left pubis, and appends a full description of the bone. 

 He furthermore gives a critical account of our knowledge of other 

 pelvic bones of the genus, and is led to associate A>/afha'.tmus, 

 Crafceomns, Omosanrus, and Polacunthus in near alliaoce, in the 

 8celidosaurian division of the Order Oraithischla. 



December 23, 1891.— W. H. Hudleston, Esq., il.A., F.R.S., 

 Yice-President, in the Chair. 



The following communication was read ; — 



"On Part of the Pelvis of PoIacantJius." By P. Lydekker, Esq., 

 B.A., F.G.S. 



The specimen described iu this paper was ac(juired by the British 

 Museum fi-om the collection of the late ^Ir. Beckles, and is from the 

 Wealden, probably of the Isle of Wight. It is the central part of 

 a Dinosaurian ilium, with portions of sacral ribs attached. 



The point of special interest is a flat plate of bone, evidently a 

 portion of dermal armour, resting on the upper border of the ilium ; 

 and this suggests comparison of the specimen with the dorsal shield 

 of Polacanthns Fo.vii. Such a comparison shows that the present 

 specimen belonged to a Dinosaur closely allied to, if not identical 

 with, P. Foxii. 



January 6, 1892,— AY. H. Hudleston, Esq., M.A., F.R.S., 

 Vice-President, in the Chair. 



The following communic:itions were read: — 



1. " On a new Form of Agi'Iacriiiiles (LejvducUscus Millen, n. sp.) 

 from the Lower Carboniferous Limestone of Cumberland.*' Bv G. 

 Sharman, Esq., and E. T. Newton, Esq., F.G.S. 



Among a large series of fossils obtained during the Geological 

 Survey of Cumberland and Nortliuniberland, there are two which 

 are referable to that remarkable and rare group of Echinoderms, 

 the Agelacrinitidic. The more perfect of these .<!pecimens is from 

 the Lower Carboniferous rocks near Waterliead, on the Kiver 

 Irthing, and forms the subject of this communication. The disc- 

 like fossil is only about fonr-tenths of an inch in diameter, and 

 scarcely rises above the shell to which it is attached ; nevertheless, it 

 is so well preserved as to allow much of its structure to be studied. 

 It is lelrrred to tlie genus L('i>ido(fisciii<, and is soeminglv closely 



