240 Royal Society, London. 



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 its 

 strobili also. 1 ) 



2. The deeply divided palmatifid sporophylls agreeing with the 

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



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

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

 Sphenophyllum Daicsoni, or S. cuneifolium, according to M. Zeiller's 

 interpretation. 2 ) 



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 case, 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, 3 ) as in Spjhenophyllum 

 Stephanense. 



6. The attachment of the sporangia, at the end remote from 

 the axis, to the laminar expansion of the sporangiophore. As 

 regards this points, comparison should be made with the Boiomanites 

 Roemeri of Count Solms-Laubach (loc. cit.). 



7. The structure of the sporangial wall. 



I think that the sura of these characters, to wich others might 

 be added, justifies the Suggestion that Cheirostrobus raay 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 occasion. 



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 lying at the common base of these 

 two series. 



It appears likely that in Cheirostrobus one of those additional 

 lorms of Palaeozoic Cryptogams , allowing of comparison with 

 Sphenophyllum has actually been brought to light, the discovery 

 of which Dr. William son and 1 ventured to anticipate at the 

 close of our first Joint memoirs. 4 ) 



l ) „Bowmanites Roemeri, eine neue Sphenoph i/llum - Fructification. ' 1895. 

 p. '242. 



8 ) „Etüde sur la Constitution de l'appareil fructificativ des Sphenophyllum." 

 (Mem. de la Soc. G<k>l. de France. Paläontologie. II. 1893. p. 37.) 



s ) Cf. Renault, „Cours de Botanique fossile," Vol. II. PI. 14. 6g. 2 

 PI. 15. fig. 3. Vol. IV. p. 15. 



4 ) Williamson and Scott, „Furtber observations on the Organisation 

 of the fossil plants of the coal-measnres." Part I. („Phil. Trans. 1894. B* 

 p. 946.) 



