268 Professor Owen on Metamorphosis and Metagenesis. 



recent memoir, published by the American Academy of Arts 

 and Sciences at Boston. The relations in structure between 

 plants and polyps might be further dwelt upon ; but for other 

 observations the writer would refer to his volume on Zoo- 

 phytes. 



The only point in which the analogy seems to fail, is that 

 the Medusa bud falls off before its full development, while 

 this is not so with the plants. But it is obvious that this is 

 unimportant in its bearing on this subject. It is a consequence 

 of the grand difference in the mode of nutrition in the two 

 kingdoms of nature ; for the plant-bud on separation loses its 

 only means of nutriment. 



The law of alternating generations is therefore no limited 

 principle, strange and anomalous, applying only to a few 

 Radiata. It embraces under its scope, the vegetable king- 

 dom, and it is but another instance of identity in the laws of 

 growth in the two great departments of life. — Dr W» B. 

 Carpenter and James D. Dana. 



Professor Owen on Metamorphosis and Metagenesis, Being 

 abstract of a Lecture delivered by him at the Royal Insti- 

 tute of Great Britain in February 1851.* 



The Lecturer commenced by passing under review the Lin- 

 naean characters of Minerals, Vegetables, and Animals, and 

 the subsequent distinctions which had been proposed for the 

 discrimination of the two latter kingdoms of nature. After 

 discussing those founded on motion, the stomach, the respira- 

 tory products, the composition of the tissues, and the sources 

 of nourishment, it was shewn that none of these singly, define 

 absolutely the boundaries between plants and animals ; it 

 requires that a certain proportion of the supposed character- 

 istics should be combined for that purpose. 



The individuals in which such characters are combined are 

 specially defined members of one great family of organised 



* The above important abstract was communicated to us by the author at 

 our request Edit. 



