110 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Jan. 8, 



some instances surrounded by much smaller vessels (b b), than in the 

 specimen first described ; but the outer range of vessels next the 

 vascular radiating cylinder (b b) is, like it, composed of smaller vessels. 

 The extremely minute vessels (a" a") seen in the longitudinal section 

 of the central axis show a remarkably delicate tissue, of which the 

 first specimen exhibits no trace. The inner cylinder is more perfect 

 than that first described, owing to the transverse section being cut 

 truer, or being better preserved, than that specimen : but the vessels 

 are of the same size with relation to the larger ones in the centre ; 

 they are barred with striae on all their sides ; and the tangential 

 section shows the small openings for conveying vascular bundles from 

 the axis to the leaves, which is not shown in the first specimen. In 

 all respects as to its internal structure, so far as it can be examined, 

 it is the same as Fo. 1, with the exception of the small vessels in the 

 central axis (a" a"), which have not yet been seen in that specimen. 



No. 3 is an oval specimen, its original circular form having been 

 changed by pressure. It is ^ths of an inch across its greater, and 

 -j^ths of an inch across its lesser axis. The external characters are 

 well shown all round the specimen ; and the scars are more elongated 

 and placed further apart than in either of those previously described. 

 Like No. 1, the scars have in their middle along their greater axis 

 a depression, in the centre of which is a small projection, to which 

 the leaf was attached. The appearance of the scar somewhat re- 

 sembles those of a Knorria described by Goldenberg*. An oblique 

 fracture of a portion of the stem displays the position of the vascular 

 bundles which traverse the stem and communicate between the 

 central axis and the leaves (PI. VI.). 



The central axis much resembles that of No. 2, especially in the 

 fact of the large hexagonal vessels in the middle being replaced and 

 parted by smaller ones, and appearing in more regular order near 

 the circumference ; but the radiating cylinder of barred vessels de- 

 scribed in specimens Nos. 1 and 2 is wanting, and a band of fine cel- 

 lular tissue appears to occupy its place. This tissue has, for the most 

 part, been destroyed in the specimen ; but traces of it are left in por- 

 tions, showing numerous round bundles of fine vascular tissue tra- 

 versing it, springing from the side of the central axis and extending 

 to the leaves, similar to those bundles described in the two preceding 

 specimens as occurring on the outside of the vascular cylinder. In 

 this specimen a zone of coarse cellular tissue bounds the band of fine 

 cellular tissue last described. A small space then appears which 

 has been for the most part destroyed, but traces of the vascular 

 bundles traversing the stem are met with at intervals. Then again 

 coarse cellular tissue occurs, which graduates into small elongated 

 cellular tissue or utricles of hexagonal form, arranged in radiating 

 series similar to that seen in Nos. 1 and 2, and most probably form- 

 ing the bark of the stem. 



In the longitudinal section of the vascular axis about the centre 



* Flora Saraepontana fossilis. Die Pflanzenversteinerungen des Steinkohlen- 

 gebirges von Saarbriicken. 18o5, pi. iv. fig. 8a. 



