ji CONTENT?. 



JimwiVh Meteorological Observations made at Fort Van- 

 couver, from June 7- 1833, to May 31. 1834. By 

 Dr M. Gairdner. Communicated by the Au- 

 thor, 67 



VlL On the Chalk and Flint of Yorkshire, as compared 

 with the Chalk and Flint of the Southern Coun- 

 ties of England. By James Mitchell, LL. D. 

 F. G. S. Communicated by the Author, - 68 



VIIL On the Infra-orbital Cavities in Deers and Ante- 

 lopes, called Larmiers by the older French Na- i^^A 

 turalists. By Arthur Jacob, M. D., Professor 

 of Anatomy in the Royal College of Surgeons in 

 Ireland. Communicated by the Author, - 7^ 



JXv Remarks on the Difficulty of distinguishing certain . 

 Genera of Testaceous Mollusca by their Shells ^ 

 alone, and on the Anomalies in regard to Habita- 

 tion observed in certain Species. By John Ed- 

 ward Gray, Esq. F. R. S. &c. - - - 79 

 I. On Shells apparently similar, but belonging, i 

 on a comparison of their Animals, to very 

 different Genera, - - . QJ 



II. Of Species belonging to the same natural 

 Genus, inhabiting essentially different si- 

 tuations, - • - - - 86 



X* On some Circumstances connected with the Original 

 Suggestion of the Modern Arctic Expeditions. 

 Communicated by the Rev. W. Scoresby, B. D., 93 



XL On the Causes of Obstruction in Water-pipes and 

 Syphons from Disengaged Air ; and on' the Con- 

 struction of a Hydraulic Air-extractor for Remov- 

 ing them. By J. Stewart Hepburn, Esq. of 

 Colquhalzie, Mem. Soc. Arts, - - IQO 



Report by Mr Dunn, - - , • 112 

 Report by Mr George Buchanan, - - ih. 

 Report by Mr Clerk Maxwell, - . |13 



Copy Letter from James Hunter, Esq. of Thur- 

 ston, to the Chairman of the Water Company, 

 . Edinburgh, dated 20th January 1821, referred 

 to in the previous Report, 



