of Fossil Cone from the Calciferous Sandstone. 423 



agree. In other respects the differences from any Lepidodendroid 

 fructification are as great as they can be. 



I do not doubt that the genus with which Cheirostrobus has most 

 in common is Sphenophyllum. The chief points of agreement are as 

 follows. 



1. The superposed foliar whorls. This certainly agrees with the 

 vegetative parts of Sphenophyllum, and, according to Count Solms- 

 Laubach, the superposition holds good for the bracts of the strobili 

 also.* 



2. The deeply divided palmatifid sporophylls agreeing with the 

 leaves of various species of Sphenophyllum, e.g., 8. tenerrimum. 



3. The division of the sporophyll into a superior or ventral, and 

 an inferior or dorsal, lobe, agreeing with the arrangement in 

 'Sphewophyllum Dawsoni, or 8. cuneifolium, according to M. Zeiller's 

 interpretation.f 



4. The differentiation of the sporophyll into sterile segments 

 (bracts) and fertile segments (sporangiophores). The comparison 

 with Sphenophyllum is much strengthened if, as I believe to be the 

 43ase, the segments of the inferior lobe in Cheirostrobus are sterile, 

 and those of the superior lobe fertile. 



5. The repeated subdivision of the leaf-trace vascular bundles, in 

 passing through the cortex of the axis,J as in Sphenophylhim 

 Stephanense. 



6. The attachment of the sporangia to a laminar expansion at the 

 distal end of the sporangiophore. As regards this point, comparison 

 should be made with the Bowmanites Romeri of Count Solms-Lau- 

 bach (loc. cit.). 



7. The structure of the sporangial wall. 



I think that the sum of these characters, to which others might be 

 added, justifies the suggestion that Cheirostrobus may be provisionally 

 placed in the same phylum, or main division, of Pteridophyta, with 

 Sphenophyllum, though indications of possible affinities in other 

 directions are not wanting, and will be discussed on another occa- 

 sion. 



Cheirostrobus, even more than Sphenophyllum itself, appears to 

 combine Calamarian with Lycopodiaceous characters, and might 

 reasonably be regarded as a highly specialised representative of an 

 ancient group of plants which lay at the common base of these two 

 series. 



It appears likely that in Cheirostrobus one of those additional forms 



* ' Bowmanites Romeri, eine neue Sphenophylleen Fructification,' 1895, p. 242. 



t " Etude sur la constitution de 1'appareil fructificative des Sphenophyllum." 

 * Mem. de la Soc. Q-eol. de France, Paleontologie,' Mem. 11, 1893, p. 37. 



J Cf. Renault, ' Cours de Botanique fossile,' vol. 2, PL 14, fig. 2 ; PL 15, fig. 3, 

 Tol. 4, p. 15. 



VOL. LX. 2 K 



