2 HiCKLING, Anatomy of CalainostacJiys Binneycxiia. 



throw light on its phylogenetic relations. It has been 

 found possible to add very little to what has already been 

 described, yet my investigations lead me to make such 

 amendments to the current interpretation of the anato- 

 mical structure as I think justify their publication. The 

 current view appears to me to require correction in two 

 important points. In the first place, I believe there is 

 ample proof that the so-called "sporangiophore" or 

 " fertile-" nodes should not be regarded as nodes in the 

 same sense as the true or" bract-" nodes at all. Secondly, 

 I believe the old descriptions were strictly correct (see e.g. 

 Hick, '92) which stated that the axis in the more common 

 cases contained three vascular bundles, not three pairs, as 

 now commonly interpreted. It is believed to be possible 

 to show that the sporangiophore-trace virtually arises at 

 the subjacent "bract-node." It is also shown that in one 

 and the same cone the conditions of 3, 4, and 6 vascular 

 bundles in the stele may coexist. In the course of the 

 work it has been proved possible to extend the method 

 of Prof Sollas for obtaining serial sections to histological 

 work, by slowly grinding down the petrified material and 

 taking microphotographs, by reflected light, of the suc- 

 cessively exposed surfaces (see Photo. 4 of P /ate). 



Turning first to the morphological character of the 

 " sporangiophore-nodes," we have the following evidence : 

 In small vegetative stems of Calamites, the nodes are 

 characterised by a strong development of " nodal wood," 

 and by the obliteration of the carinal canals of the 

 bundles. The medulla commonly persists in the form of 

 nodal diaphragms, composed of very short cells. In 

 impressions, the node always appears as a distinct 

 "joint." Precisely the same features mark the true or 

 bract-nodes of the cone, with just this difference ; that as 

 the whole medulla is persistent, instead of nodal dia- 



