68 Geological Society : — 



Calculated. Found (mean). 



Ag 3 =324-0 7375 73-83 



V = 51-3 11-67 11*76 



4 = 640 14-58 



439-3 100-00 



2. The Tetrabasic Silver Vanadate, Ag 4 P 2 7 , is prepared by- 

 mixing a solution of the corresponding sodium salt with a neutral 

 solution of nitrate of silver. It falls as a yellow dense crystalline 

 precipitate, resembling in colour the ordinary phosphate of silver. 

 On dissolving the salt in nitric acid, the silver is precipitated as chlo- 

 ride, and the vanadium determined as V 2 O.. 



Analysis gave : — 



Calculated. Found. 



Ag 4 =432 66-81 66-45 



V a = 102-6 15-87 15-97 



O = 112-0 17'32 



646-6 100-00 



The reactions of the tri- and tetrabasic vanadates of the other 

 metals are then described. 



The author has to thank Messrs. Oelhofer and Finkelstein for the 

 valuable assistance which they have given him in the above investi- 

 gation. 



GEOLOGICAL SOCIETY. 



[Continued from vol. xxxix. p. 463.] 



November 10th, 1869.— Prof. T. H. Huxley, LL.D., F.P.S., 

 President, in the Chair. 



The following communications were read : — 



3. " On Hypsilophodon, a new Genus of Dinosaima." By Pro- 

 fessor Huxley, F.R.S., President. 



The author described the characters presented by the skull of a 

 small Dinosaurian reptile obtained by the Pev. W. Fox from a 

 "Weaklen bed at Cowleaze Chine in the Isle of Wight. One of the 

 most striking peculiarities of this skull was presented by the prse- 

 maxillary bone, which seems to have been produced downwards 

 and forwards into a short edentulous beak-like process, the outer 

 surface of which is rugose and pitted. The author remarked upon 

 the known form of the symphysial portion of the lower jaw in the 

 Dinosauria, and indicated that its peculiar emargination was pro- 

 bably destined to receive this beak-like process of the prsemaxillaries, 

 which may have been covered either by fleshy lips or by a horny 

 beak. The dentigerous portion of the praemaxiUa bears five small 

 conical teeth. The alveolar margin of the maxilla bears ten teeth, 



