dry land at this early period of creation. From the earliest beginning 

 of life in this period until the introduction of llslaes there is a series 

 of gi-adual changes in the character of the animals and plants, but no 

 sudden cataclysms or miraculous creations. The new forms which 

 appear are intermingled more or less with the old, and the whole is a 

 gradual progression, in which tlie first created and simplest are almost 

 imperceptibly supplanted by more highly organized beings. 



Mr. F. W. Putnam followed Mr. Hyatt, and alluded to the fact that 

 Lake Champlain having been an estuary of the ocean at a compara- 

 tively recent period, that of the Quaternary, as shown by the remains 

 of marine shells and other marine animals found in the clay banks of 

 the lake were identical with species now living on the coast of 

 Maine. 



It is a matter of some interest to ascertain w^here the fresh water 

 fishes and other animals now inhabiting the lake came from. On 

 making a comparison of the fishes of Lake Erie with those of Lake 

 Champlain he was satisfied that the majority of the species were the 

 same, and that Lake Champlain had been supplied with its inhabitants 

 from the Great Lakes and the rivers fiowing into the lake. 



Mr. E. S. Morse stated that the same faunal connection was shown 

 in the mollusca of that lake, and mentioned several species identical 

 with those of the Great Lakes and unlike any found east of Lake 

 Champlain. 



Mr. MoKSE mentioned that he had found among the collection of 

 shells made by Mr. Joseph True of Salem, which had been presented 

 to the cabinets of the Institute by a friend, several interesting speci- 

 mens, one of which, a species of Limnadia, belonging to the order of 

 Phyllopoda, appeared to be entirely new. 



The following communication was received from Charles Wright, 

 of Cambridge : 



Ammannia lingulata, Gris. : — Mr. Grisebach established this spe- 

 cies on specimens from Cuba, and it may interest botanists to know 

 that it belongs also to the United States. The only distinctive 

 character assigned is the short style. This at once suggested the 

 idea that it might be a case of dimorphism now known to be 

 so common. As I have just given these plants a patient examination 

 I will state the conclusions to which I have come. So far as the 

 specimens at my disposal indicate, A. Hngulata Gris. is a stout plant, 

 with larger flowers, larger fruit and seeds, twice the size of those of 

 A. Jatifolia Linn, as well as difierent in form and color. These all, of 

 themselves, would not be sufficient, perhaps, if the dimorphism could 

 be shown. But in this latter case, generally, if not alwaj's, the extra- 

 oi'dinary development of one organ or set of organs is accompanied 

 by the greater or less reduction of the other. In our plant such is not 

 the cape. The stamens and style are quite hidden within the calyx," 

 and the filaments are very short, while in A. latifoUa both are ex- 

 serted. It is, however, but fair to say, that in a specimen from 

 Illinois, I saw one or two styles somewhat lengthened. I have exam- 

 ined specimens of Ammannia humilis and find in them no sign of 

 dimorphism. 



The seeds of A. latifolia are darker in color, or of a light brownish, 



