340 DR D. H. SCOTT ON THE 



medullary rays one, or at most two cells in thickness. The inner part of the wood 

 consists of short broad tracheides, with a tortuous course. 



The reasons for placing this species in the genus Calamopitys of Unger may now be 

 briefly considered. This genus was established by Unger on the species C. Saturni in 

 1856, # but our present accurate knowledge of its structure is due entirely to the 

 recent work of Count SoLMS-LAUBACH,t who has further shown that Unger's Stigmaria 

 annularis was also a Calamopitys, scarcely distinct from the original species. The 

 generic name Calamopitys, which expressed Unger's view of the Calamarian affinities 

 of his fossil, is entirely inappropriate, and the real relationships of the genus have 

 proved to lie in quite a different direction. The old name is kept up simply in order 

 to avoid burdening the synonymy with a new one. 



In the specimens of Calamopitys Saturni there is a small pith (only about 1-2 mm. 

 in diameter) surrounded by an irregular tracheal zone, reduced or perhaps wholly inter- 

 rupted at certain points, and forming enlarged nests between them, each such nest 

 having a central group of small elements, presumably the protoxylem. This zone of 

 primary xylem is surrounded by the secondary wood, the tracheides of which have small 

 narrow circular pits ranged in several rows on their radial walls. The medullary rays 

 are usually pluriseriate. Some remains of the phloem have been found, and the cortex 

 is well shown ; in its inner part it consists of parenchyma, while towards the periphery 

 it contains parallel bands of hypodermal fibres, thus having the well-known ' Sparganum ' 

 structure. In the cortex the leaf-trace bundles are also found ; their course has been 

 followed with great completeness, in successive transverse sections, by Count Solms- 

 Laubach, who finds that a single bundle leaves the wood, and at first (as in Lygino- 

 dendron) is accompanied by secondary xylem. The leaf-trace divides into two on 

 entering the cortex, then into four, and finally into six ; the six resulting bundles enter 

 one of the leaf-bases which are found attached to the stem. The leaf-stalk has the 

 structure of Kalymma, and as Kalymma is known to have branched, the inference is 

 that the leaves of Calamopitys were compound. Count Solms-Laubach has shown 

 beyond doubt that the phyllotaxis was 2/5, or extremely near it. In the form 

 referred to C. annularis, the primary wood is more extensive, and apparently more con- 

 tinuous ; in some of the specimens the pith attains a diameter of 7 mm. In other 

 respects there is no important difference between C. annularis and C. Saturni, and it is 

 not even certain that the species were really distinct. Both forms belong to the Culm, 

 or Lower Carboniferous, of Central Germany, and are thus of similar horizon to that of 

 the British species. 



In comparing the German species of Calamopitys with our own fossil, we are 

 unfortunately restricted to characters presented by the pith and wood, for these parts 

 are alone preserved in the British specimens. Count Solms-Laubach most kindly lent 



* Richter u. Unger, Beitrag z. Palxont. d. Thiiringer W aides, Denkschr. d. K. K. Alcad. zu Wien, math, naturw. CI. 

 Bd. xi., 1856. 



t Pflanzenreste des Unterculm v. Saalfeld in Tliiiringen — Abh. d. K. Preuss. Geol. Landesanstalt, Heft 23, 1896, p. 63, 

 Taf. IV. 



