1867.1 333 f^o""^- 



Royal Academy at Munich ; from the Royal Dublin Society ; 

 from the London Geological Society; from the London Me- 

 teorological Society ; from the Royal Asiatic Society, Lon- 

 don ; from the Royal Institution of Great Britain ; from the 

 Ordnance Survey Office of England ; and from the Franklin 

 Institute. 



Mr. Fraley announced the death of John Penington, a 

 member, which occurred on the 18th March, 1867, in the 68th 

 year of his age. 



Mr. P. E. Chase made some remarks upon an apparent 

 discrepancy between the tidal theories of Delauncy and Airey. 



Dr. II. C. Wood, Jr., made the following remarks : 



Mr. President: My apology for the following account of some 

 investigations, which I have recently been engaged in making, must 

 be the interest they have excited in myself, and the fact, that they 

 are confirmatory of the life history of the European congeners of the 

 plant, as worked out by Pringsheim, Henfrey, and others, and that 

 they are the first observations that I know of on an American form. 

 The little plant constitutes the filamentous confervoid growth, which 

 has so annoyed the aquaria cultivators in this city. The specimens 

 which were studied, grew spontaneously on the Hornwort (Cerato- 

 pliyllum) in my aquarium. It without doubt belongs to the genus 

 CEdogonium. The growth of the filament takes place by the forma- 

 tion of new cells, both amongst the older ones and at the distal free 

 end. When an old cell is about to undergo division, a small streak- 

 like fissure appears near its distal end, dividing entirely the outer 

 cellulose wall. This takes place principally in those cells which are 

 well filled with a greenish granular protoplasm. The latter now in- 

 creases in length, becoming at the same time less dense, more trans- 

 parent, and soon separates the two sundered parts of the old cell- 

 walls, bearing the upper portion like a little cap on its distal end. 

 As soon as the fissure is well pronounced, a partition separating the 

 lower portion of the old cell begins to be apparent, and the new por- 

 tion is cut oif and commences its existence as an independent cell. 

 In a very little while a cellulose wall is formed, and the cell having 

 attained sufficient size, recommences the process which gave it birth. 



The distal cells appear to grow by a kind of pullulation, from the 

 primordial utricle, a portion of the distal end of the terminal cell 

 elongating into a long cell, whose calibre of course does not equal that 



