NATURAL SCIENCES OF PHILADELPHIA. 113 



Descriptions of new species of Fresh Water Mollusca, from Panama. 

 By Geo. W. Tryon, Jr. 



Description of a new Exotic Melania. By G. W. Tryon, Jr. 



Descriptions of new species of fresh water Mollusca, &c. By Geo. 

 W. Tryon, Jr. 



Notes on the Birds of Jamaica. By W. T. March, with remarks, 

 by S. F. Baird. 



On a third kingdom of organized bodies. By T. B. Wilson, M. D., 

 and John Cassin. 



Descriptions of fourteen new species of Melanidoe and one Paludina. 

 By Isaac Lea. 



May 2Qth. 

 The President, Mr Lea, in the Chair. 



Nineteen members present. 



On Report of the respective committees, the two papers of Mr. Lea, 

 read May 12th, were ordered to be published in the Journal, and the 

 following were ordered to be published in the Proceedings : 



On a Third Kingdom of Organized Beings. 

 BY THOMAS B. WILSON, M. D., AND JOHN CASSIN. 



The classification of the lower forms of organized beings, on the assumption 

 that they ought to be assigned to either the animal or the vegetable kingdom, 

 has presented difficulties to naturalists which have proved insurmountable. 

 The position of entire groups remains, apparently, as uncertain and undeter- 

 mined in this respect as it ever was, and the conclusions and opinions of 

 authors are so various that it is palpable that no considerable approach has 

 been made to the solution of the questions involved, notwithstanding much 

 very careful and accurate investigation and patient research. The difficulty 

 probably originates in the first assumption, that all organized or living beings 

 are referable to two great groups only, an assumption and presupposition of 

 almost universal prevalence, but in which men of science seem to have been 

 contented to adopt popular belief and to accept the usual and popular appli- 

 cation of language. There are, very probably, three kingdoms or great pri- 

 mary groups of organized beings, as distinct from each other as any subordi- 

 nate groups and as readily defined by valid and recognizable characters. 



Whatever may be the solution, ultimately, of the very important questions 

 relating to the primary, and at present unknown, principles under which the 

 normal and inherent forces of Nature first assume that mysterious tension or 

 condition, of which life is the immediate result, it is evident and unmistaka- 

 ble that this extraordinary tension manifests itself and operates under such 

 controlling laws that its results are determinate and uniform. Taking on 

 themselves isolation from the great mass of inorganic Nature, though tempo- 

 rarily only, these forces assume developments which are circumscribed and 

 specific, though evidently progressive and modified under circumstances coin- 

 cident with and dependent upon the laws or conditions of existence of organic 

 life in any geologic period. It has hitherto been assumed, apparently, that 

 from a point of the first manifestation of life, its progress of evolution or de- 

 velopment is into two series or great classes of existences, animal and vege- 

 table, or perhaps into one series only, according to the hypotheses of the 

 older authors, regarded as the chain of being, from the lowest vegetable to 



1863.] 9 



