86 Proceedings of the Royal Physical Society. 



A portion of his Memoir X. ^ is also devoted to an exami- 

 nation of fossil spores, some of which are figured. This 

 Memoir also contains a critical examination of the bodies 

 described by Mr Carruthers as Traqiiairia?' The result of 

 Professor Williamson's investigation into the nature of 

 Traquairia shows that these organisms are Lycopodiaceous 

 macrospores, and not Eadiolarians as supposed by Mr 

 Carruthers. These fossils have, therefore, been classed as 

 Lcpidostrohus Traqiiairia. 



In 1884, Dr Keinsch published a work in two volumes, 

 entitled " Micro-Palseo-Phytologia Pormationis Carboniferae," 

 in which are given over a hundred plates of micro-organisms, 

 the greater portion of which are spores. Of diese, however, 

 we must restrict our remarks to those groups only which affect 

 that branch of the subject especially engaging our present 

 attention. Possil spores are divided by Dr Eeinsch into 

 various groups, and of these Triletes is the one to which 

 most of our macrospores must be referred. 



Triletes, as employed by Dr Pieinsch, may be thus defined : 

 More or less triangular, semi-elliptical or circular bodies, 

 usually occurring as compressed discs, outer surface variously 

 ornamented, but always showing three converging ridges. 



These spores, though now usually occurring as flattened 

 discs, were, of course, originally more or less globular, the 

 flattening in all cases being due to pressure. Triletes must 

 not be regarded as a genus, for the occurrence of a triradiate 

 ridge, one of the chief characters of the group, though 

 common to the spores of the Lycopodiacese-, also occurs on 

 the spores of other Orders.^ It is necessary, however, for 

 the purpose of reference, to give names to such organisms, 

 even although only provisionally applied. We believe, how- 

 ever, there is little reason to doubt that all the forms of Triletes 

 about to be described, are referable to some of the extinct 

 Lycoi^odiacem {Lepidodendron, Lepidophloios, and Sigillaria). 



There is another group of organisms described by Dr 

 Eeinsch, to which we must also refer. This is his Stelidem. 



1 Phil. Trans., Part ii., 1880, p. 493. 



2 Rep. of Brit. Assoc, for 1872 : Trans, of Sections, p. 126. 

 ^ As on the spores of Sphagnum, etc. 



