OF THE FOSSIL PLANTS OF THE COAL-MEASUEES. 
23 
may be the meaning of the prevalence of exogenous development amongst the Crypto- 
gams of the Carboniferous epoch, it clearly has no relation to mere size. 
Since the plant now described is remarkably different from any hitherto noticed, I 
propose to assign to it the generic title of Kaloxylon, and to identify it with the name 
of our distinguished President as Kaloxylon Hookeri. 
All the specimens which I have figured are from the Oldham Upper foot-coal. But 
I have found two or three sections of very young branches, in the condition of that 
represented in the upper part of fig. 34, amongst my sections of specimens from Burnt- 
island. This circumstance indicates that the genus has had a considerable vertical 
range, and hence may be expected to occur in some of the continental deposits like those 
of Autun and St. Etienne, whence I trust that M. Renault or M. de Grand-Eury will 
soon succeed in disinterring it. 
Index to the Plates. 
Myelojpteris ( Medullosa of Cotta). 
Plate 1. fig. 1. Transverse section of a petiole. Enlarged 10 diameters. 
„ fig. 2. Vertical section of part of a similar specimen to fig. 1. Enlarged 20 dia- 
meters. 
„ fig. 3. Transverse section of a young or of the upper portion of a rachis. 
Enlarged 20 diameters. 
„ fig. 4. Similar section to fig. 3. 
„ fig. 4*. Transverse section made very near to the terminal portion of a rachis. 
Enlarged 40 diameters. 
Plate 2. fig. 5. Longitudinal section of a very young rachis, with the bases of two leaflet- 
petioles. Enlarged 16 diameters. 
„ fig. 6. Part of a longitudinal section of a young petiole, with traces of large 
prosenchymatous cells occupying a gum-canal, c. Enlarged 65 dia- 
meters. 
„ fig. 7. Transverse section of a vascular bundle of a petiole from Capt. J. Aitken’s 
specimen. Enlarged 97 diameters. 
„ fig. 7*. Transverse section of a vascular bundle from Mr. Carruthers’s specimen. 
,, fig. 8. Longitudinal section of fig. 7. Enlarged 97 diameters. 
Plate 3. fig. 9. Transverse section of part of a petiole in which no gum-canals exist in 
contact with the vascular bundles. Enlarged 65 diameters. 
Plate 1. fig. 10. Longitudinal section of a vascular bundle of fig. 9, exhibiting the 
elongated cells constituting the imperfect bundle-sheath. Enlarged 
65 diameters. 
Plate 2. fig. 11. Transverse section of a vascular bundle from the periphery of fig. 1, 
with very few vessels in it. Enlarged 65 diameters. 
