418 Proceedings of the Royal Physical Society. 



The only species to which Sigillaria McMiirtriei has any 

 resemblance is Sigillaria tumida, Bunbury, sp. {Le^pidoden- 

 dron ? tumidum, Quart. Journ. Geol. Soc, vol. iii., p. 432, pi. 

 xxiv., fig. 1). From this species it differs in the form of 

 its leaf-cushions. The surface-ornamentation in Sigillaria 

 tumida also differs in being '' rather irregular, wavy, longitu- 

 dinal stride." 



Bunbury described his plant as Lepidodendron ? tumidum, 

 and Schimper places it in Zepidophloios ; ^ but I believe that 

 this plant is also a Sigillaria. 



In his description Bunbury does not mention the form of 

 the lateral cicatricules, nor does his drawing show it very 

 clearly ; but he says the central cicatricule consists of " two 

 vascular points placed close together and often confluent." 



In some of the leaf-scars of Sigillaria McMurtriei there is 

 the same appearance in the central vascular cicatricule (see 

 Fig. 3&). A similar structure occurs in the vascular impres- 

 sion of Sigillaria Lorwayana, Dawson.^ 



In Sigillaria' Moureti, Zeiller,^ a somewhat similar structure 

 of the vascular cicatricule also occurs. 



I have entered very fully into the description of Sigillaria 

 McMurtriei to show that it is a true member of the genus 

 Sigillaria ; and from the great similarity of Zejndodendron ? 

 tumidum, Bunbury, to Sigillaria McMurtriei in all general 

 points, I think there cannot remain any doubt as to its also 

 being a Clathrarian Sigillaria. Bunbury himself expresses 

 his dif&culty in regard to the position of his plant, and says 

 that it would be referred by some to Zepidodendron, and by 

 others to Sigillaria. 



I first observed this species in the collection of Mr J. 

 McMurtrie, Ptadstock, after whom I have great pleasure in 

 naming it. Mr McMurtrie has not only carefully collected 

 the fossil plants of the Eadstock Coal-field, but has done 

 much to elucidate the geology of his neighbourhood. I also 



1 Scliiraper, Traite d. paleont. veget,, vol. ii., p. 52. 



2 Dawson, "Fossil Plants of Lower Carboniferous and Millstone-Grit 

 Formations of Canada," p. 43 (woodcut), 1873. 



3 Zeiller, Bull. Soc. Geol. de France, 3^ ser., vol. viii., p. 210, pi. v., fig. 3. 



