272 Contributions towards Establishing the General Character 



haling pure air during night as well as day, in cold or warm 

 climates, increased longevity will be attained, and, at all 

 events, the general comfort improved; and as Britain has 

 outstripped most nations in the application of steam-power to 

 useful purposes, why should she not take the lead in culti- 

 vating those arts which the physiologist has proved to be essen- 

 tial to the advancement of the physical condition of mankind X 



Contributions torvards Establishing the General Character of 

 the Fossil Plants of the genus Sigillaria. By William King, 

 Esq., Curator of the Museum of the Natural History So- 

 ciety of Northumberland, Durham, and Newcastle-upon- 

 Tyne. With two Plates. (Communicated by the Author.) 



(CJontinued from page 21.) 



A consideration of the ribs and furrows of Sigillaria will now engage 

 our attention. From these characters, Lindley and Hutton appear to 

 think, that the plants of this genus are allied to Cactidce and Euphorhidce. 

 To these families, it is said, they seem to approach, particularly in their 

 soft texture, in their deeply channelled stems, and especially in their 

 scars being placed in perpendicular rows between the furrows.* Brong- 

 niart also refers to the resemblance between the external characters 

 of the latter plants and those of Sunllaria. From what is stated when 

 speaking of the internal structure of certain Cactuses, it may be inferred, 

 that he supposes their ribs and furrows to be, in a measure, due to the 

 same characters observable on the external surface of their ligneous 

 cylinder, t I mention this to ward off the notion that the ribs and fur- 

 rows of Sigillaria arise from the same cause, judging from S. elegans, 

 because in this species the ligneous cylinder has no appearance of being 

 externally fluted. 



Brongniart, in his general observations on Sigillaria, makes a slight 

 allusion to the resemblance between the longitudinal ribs of S. Sillimani 

 and S. contracta, and those of some arborescent ferns. J Having had no 

 opportunity of studying the latter, I have been compelled to examine 

 more accessible plants, with the view of ascertaining if the like character 

 occurs on any of their stems. Hitherto I have met with the most 

 success among the Conifers. The surface of young shoots of the larch 

 (Larix Europcea), and the spruce (Abies exeelsa), are irregularly ribbed and 



• " Fossil Flora," vol. i. p. 165. 



t " Archives du Musuem d'Histoire Nat urelle," tome i. pp.442, 443. 1839. 



J " Histoire des Vegetaux Fossiles," tome i. p. 403. 



