Royal Institution. 59 



the external layers, minute, chlorophyllose and duet-like. Cap- 

 sules cylindi-icalj gymnostomate ? and peristomate. Teeth eight 

 or sixteen. Calyptra mitriform or dimidiate. Mosses remark- 

 able for the pale colour, iridescence, and structure of the cells of 

 their leaves : growing on the earth, on rocks, or on trees. 

 Genus 1. Octoblepharum, Hedw. 



2. Arthrocormus, Dzy. et Molk. 



3. Leucophanes, Brid. 



4. Schistomitrium, Dzy. et Molk. 



5. Leucobryum, Hampe. 



Tribe XIII. Sphagnace^. 



Cells of the leaves dimorphous, prosenchymatous, the larger 

 colourless, perforate, often containing annular fibres ; the smaller 

 chlorophyllose, placed between the larger. Capsules gjonnosto- 

 mate. Calyptra covering the whole capsule. Large mosses, with 

 erect stems, pale or rose-coloured leaves, and globose sessile cap- 

 sules : growing in bogs. 



Genus 1. Sphagnum, Dill. 



PROCEEDINGS OF LEARNED SOCIETIES. 



BOYAL INSTITUTION. 



Friday, February 7, 1851. 



On Metamorphosis and Metagenesis. By Professor Owen. 



The Lecturer commenced by passing under renew the Linnaeaii 

 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 foimded on 

 motion, the stomach, the respiratory products, the composition of the 

 tissues, and the sources of nourishment, it was shown that none of 

 these singly define absolutely the boundaries between plants and 

 animals ; it requires that a certain proportion of the supposed cha- 

 racteristics should be combined for that purpose. 



The individuals in which such characters are combined are specially 

 defined members of one great family of organized beings, and the 

 supposed peculiarly animal and vegetable characters taken singly, 

 interdigitate, as it were, and cross that debatable ground and low 

 department of the common organic world from which the specialized 

 plants and animals rise ; and there are numerous living beings with 

 the common organic characters that have not the distinctive com- 

 bined superadditions of either group. 



Between the organic and inorganic worlds the line of demarcation 

 may be more definitely drawn. The term ' growth ' cannot be used 

 in the same sense to signify the increase of a mineral and of an 

 organism. The mode of increase is different : there is a definite Umit 

 to it in the organic kingdom, and something more than mere growth 



