OF CALAMITEAN STROBILUS. 261 



Mr. Binney's. '^ The spores are simply globular bodies, fre- 

 quently exhibiting an outer and an inner wall/^ This de- 

 scription also tallies with my own; but Mr. Carruthers 

 continues, " Sometimes, however, they appear to be com- 

 posed of a single wall; and then the outer wall is represented 

 by lines more or less separated from the spores. These 

 I believe to be elaters, similar in structure to those of 

 EquisetumJ' I have found spores exhibiting something 

 of this appearance when the outer cell-membrane had been 

 broken up, either by contraction or, more especially, during 

 mineralization ; but I am satisfied that my specimen con- 

 tains no elaters. In the structure of the central axis, again, 

 we have a diflPerence. In Mr. Binney^s specimens the 

 centre of that axis is occupied by a bundle of scalariform 

 tissue. Nothing of the kind exists in my plant. Its central 

 portion presents every appearance of having been fistular, 

 or only occupied, in its young state, by cellular tissue. 

 The only vessels to be seen are in the woody axis, where 

 they are reticulated and unaccompanied by any scalari- 

 form ones. At the same time, there can be no doubt that 

 the two types are constructed upon the same general plan, 

 the differences which they present being but generic and 

 not ordinal ones. They resemble each other too closely 

 in their common features to leave a doubt that if the one 

 is Calamitean so also is the other ; and since no one appears 

 to doubt that such is the character of Mr.Binney^s strobilus, 

 I may fairly claim the same rank for my own. What, then, 

 is the signification of the points in which they differ ? It 

 will be remembered that the Calamitean stem which I 

 described under the name of Calamopitus was characterized 

 by the possession of reticulated vessels instead of the sca- 

 lariform ones common in other types of Calamite, and by a 

 peculiar arched arrangement of those scalariform vessels 

 wherever they crossed the node, which latter arrangement 

 is common to all the types of Calamite of which I have 



