264 PTERIDOPHYTA. [CH. 



but the preservation is not sufficiently good to enable one to 

 speak with certainty as to the manner of attachment. Each 

 cone consists of regular hexagonal depressions, which agree 

 exactly with the surface characters of Kidston's type-specimen. 

 The manner of occurrence of the cones points to a lateral and 

 not a terminal attachment. The stem does not show any traces 

 of Equisetaceous leaf-sheaths at the nodes, and such fragments 

 of leaves as occur appear to have the form of separate linear 

 segments; they are not such as are met with on Equisetites. 

 It agrees with some of the slender foliage-shoots of Calamitean 

 plants often described under the generic name Asterophyllites. 

 As regards the cones ; they differ from the known Calamitean 

 strobili in the absence of sterile bracts, and appear to consist 

 entirely of distally expanded sporophylls as in Equisetum. The 

 general impression afforded by the fossil is that we have not 

 sufficient evidence for definitely associating this stem and cones 

 with a true Equisetites. We may, however, adhere to this 

 generic title until more satisfactory data are available. 



2. Equisetites spatulatus Zeill. Fig. 58, A. 



This species is chosen as an example of a French Equisetites 

 of Permian age. It was recently founded by Zeiller^ on some 

 specimens of imperfect leaf-sheaths, and defined as follows : — 



Sheaths spreading, erect, formed of numerous uninerved coherent 

 leaves, convex on the dorsal surface, spatulate in form, 5 — 6 cm. in length 

 and 2 — 3 mm. broad at the base, and 5 — 10 mm. broad at the apex, 

 rounded at the distal end. 



The specimen shown in fig. o8,A, represents part of a flattened 

 sheath, the narrower crenulated end being the base of the 

 sheath. The limits of the coherent segments and the position 

 of the veins are clearly marked. Zeiller's description accurately 

 represents the character of the sheaths. They agree closely 

 with an Equisetaceous leaf-sheath, but as I have already 

 pointed out, we cannot feel certain that sheaths of this kind 

 were not originally attached to a Calamite stem. 



1 Zeiller (95). 



