IL'L> IV. .f. W. C. Willian.scn anl Dr. I>. II. Scott. [Feb. 8, 



as to preclude a near relationship. A form described by M. Renault, 

 nnder the name of Brudfrnannia Grand'Enryi, unites the external 

 morphology of a Calamostachys with the anatomy of a Calamites. It 

 is therefore possible that the species of Calamostachys considered in 

 this paper may have been borne on stems with Calamitean structure, 

 but this cannot be proved until the strobili are found in actual con- 

 tinuity with the vegetative organs. 



3. Sphenophyllum. The habit of these plants is well known. The 

 rather slender, jointed stem bore verticils of superposed leaves, the 

 number of leaves in each verticil being some multiple of 3. The 

 leaves were sometimes cuneate, sometimes dichotomously subdivided, 

 sometimes linear. 



The anatomy of several undoubted species of Sphenophyllum is now 

 known, and there is no longer any doubt that some of the fossils 

 described in previous memoirs under the name of Asterophyllitet 

 really belong to Sphenophyllum. 



The first species described is Sphenophyllum plurifoliatum = Astero- 

 phyllites sphenophylloides of the former memoirs. 



The number of leaves in each whorl was large, not less than 18. 

 They were linear in form. 



The axis is traversed by a solid vascular strand, triangular, as seen 

 in transverse section, without any pith. The strand is triarch, with 

 a group of narrow spiral and reticulate elements (protoxylem) at 

 each angle. The primary wood of the stem was thus centripetal, 

 and so far resembled that of most recent Lycopodiaceee, with which, 

 however, the genus has otherwise little in common. 



Secondary growth in thickness took place constantly, and has been 

 observed at every stage. The secondary wood consisted of radially 

 arranged trachea; (whether vessels or tracheides is doubtful) with 

 strands of parenchyma between them. The longitudinal paren- 

 chymatous strands are connected by radially elongated cells, which, 

 however, seldom form continuous medullary rays. 



The cambium is excellently preserved in some specimens, a fact 

 which removes all doubt as to the truly secondary character of the 

 tissues in question. 



The primary cortex and leaves were soon cast off by the format 

 of internal periderm. The older stems have a large amount 

 secondary tissue to the outside of the cambium. This is shown 

 consist partly of true phloem, partly of internal peridermal laye 

 which in extreme cases formed a regular scale-bark. 



A second species, Sphenophyllum insigne (= Asterophyllites ir> 

 Will.), is described. Its general anatomy agrees with that of 

 former species, apart from differences of detail. The most impor 

 structural peculiarity of S. insigne consists in the constant preset 

 of continuous medullary rays in its secondary wood. 



