194 CALAMOPITYEAE [CH. 



bundles, each being accompanied by an arc of secondary tracheids 

 which, in the cortical region, completely surrounds the primary 

 elements. At a later stage the single protoxylem of each trace 

 divides into two and before entering the leaf -base there is a further 

 division. In some specimens leaf-bases of the Kalymma type 

 were found attached to the stem. The occurrence of tracheids 

 in the axial region is a distinguishing feature and suggests a 

 comparison with Heterangium, while C. Saturni agrees more closely 

 with Lyginopteris ; the species C. annularis would appear, from 

 the recent observations of Scott and Jeffrey, to occupy an inter- 

 mediate position. 



Calamopitys, as the generic designation is here employed, is 

 confined to central Germany and Kentucky and occurs in Upper 

 Devonian and Lower Carboniferous strata. There is, however, 

 some doubt as to the exact geological horizon of the rocks in 

 both countries though in neither case is there any question of an 

 horizon higher than Lower Carboniferous. Certain specimens 

 from the Lower Carboniferous of Scotland described by Scott 1 

 as species of Calamopitys have been made by Zalessky the type 

 of a new genus, Eristophyton, and are dealt with under that name. 



Kalymma. Unger. 



Kalymma grandis (petiole of Calamopitys). Under the generic 

 name Kalymma Unger described specimens from Thuringia of 

 Upper Devonian age which he assigned to two species, K. grandis 

 and K. striatum. Solms-Laubach has shown that Kalymma is 

 not an independent stem as Unger believed but a petiole of 

 Calamopitys, and this has been confirmed by Scott and Jeffrey 

 who found a leaf-base with the Kalymma type of structure in 

 connexion with a piece of Calamopitys stem, probably C. americana. 

 An examination of a section (2-3 cm. broad) of Unger's K. grandis 

 in the collection of the Geological Survey enables me to confirm 

 the conclusions recently published by Scott and Jeffrey. The 

 best specimens of Kalymma, which appear to be identical in 

 essential features with Unger's type-species, are from Kentucky, 

 some from the Genessee shales of Upper Devonian age and others 

 from beds (Waverley shales) believed to be Lower Carboniferous. 



1 Scott (02). 



