1853.] 375 



July 5th, 1853. 

 Vice-President Bridges in the Chair. 

 The following communication from Prof. Agassiz was read : 



*' The specimen of Cambarus Gambelii liberally lent to me by the Academy 

 for comparison, has afforded most unexpected information. Why that species 

 should have been referred to the genus Cambarus by Mr. Girard, who first de- 

 scribed it, I am at a loss to ascertain, unless it be because it inhabits the United 

 States, Erichson having ascertained that there are Crawfishes with six, and 

 others with five pairs of gills, and that the species with five pairs of gills, for 

 which he proposes the name of Cambarus, live in the United States. As soon as 

 I learned that our zealous and lamented friend, Dr. Gambel, had left specimens 

 of Crawfishes from the far West, my interest was aroused to the utmost, as I 

 wanted to know whether the western range of this continent would present among 

 these animals the same diiference from those of the eastern, and the same agree- 

 ment with those of the western parts of the old world, as have already been ob- 

 served in their physical features, and in the geographical distribution of other 

 beings. My anticipation was fully justified. Cambarus Gambelii Gir., is no 

 Cambarus, though it lives in America. It has six pairs of gills, as the Craw- 

 fishes of Europe, adding another instance of the remarkable correspondence of 

 the eastern and western tracts of different countries, when compared with their 

 homonyms, and of their striking difference when opposite shores are contrasted. '* 



July 12th. 



Vice-President Bridges in the Chair. 



Letters were read 



From the Linnean Society of Lyons, dated 22d April, 1853 ; from 

 the Academy of Sciences, Belles Lettres, &c., of Lyons, of same date; 

 and from the Agricultural Society of Lyons, of same date ; severally 

 transmitting the volumes of their publications announced this evening. 



July 19th. 

 Vice-President Bridges in the Chair. 



A letter was read from Henry A. Ford, M. D., dated Glasstown, 

 Gaboon River, Africa, March 18, 1853, acknowledging the receipt of 

 his notice of election as a Correspondent, and transmitting an additional 

 collection of objects of Natural History for the Museum. 



A letter was read from Mr. Richard D. Wood, of Philadelphia, dated 

 July 12, 1853, acknowledging the receipt of his notice of election as a 

 Member. 



July 26th. 



Vice-President Bridges in the Chair. 



An amendment to Chapter 3, Art. 3, of the By-Laws, was adopted, 

 changing the amount of a life membership from fifty dollars to one hun- 

 dred dollars. 



PROCEED. ACAD. NAT. SCI. OF PHILADELPHIA, VOL. VI,, NO. X. 55 



