BIBLIOGRAPHY. 



115 



covered. It was invested with an irregular coat of mineral matter; in Avbicli were 

 observed numerous small portions of vegetable tissue, intermixed with what appear to be 

 twigs. Mr. Witham has represented this coat, charged with its vegetable fragments, in 

 pi. viii, fig. 7, of his ' Internal Structure of Fossil Plants.' The matrix, as it ought rather 

 to be called, was in immediate contact with the tissue of what we shall presently see is the 

 ligneous zone of the fossil — a circumstance which prevents us coming to any conclusion as 

 to the thickness of its bark ; for instance, whether it was thin^ like most of the Conifers, or 

 thick, as is the case with the Si(/iUari(g, the Cycases and Cactuses. Mr. Witham, in his 

 description, says that the specimen when complete was a tapering body several inches in 

 length, rounded at the extremity, and resembling the termination of a stem or branch. 

 In another part it is stated that the specimen, divested of its envelope, was compressed 

 so as to have one diameter about a half greater than the other. ' At the lower part the 

 large diameter was upwards of two inches ; and at the extremity one diameter is about 

 half an inch, the other nearly a fourth.^ I may observe that the sections before me 

 answer to these and the intermediate sizes. If we were uncertain that Anahathra pos- 

 sessed a thick bark, there is something in the description just quoted which would 

 induce one to suppose that this fossil was a short fleshy plant, resembling some of the 

 Cactuses. Let it be understood, however, that I am far from thinking that this was the 

 case. Mr. Witham states that the specimen presented the appearance of natural joints 

 at the distance of about two inches, and that its surface was slightly striated in the 

 longitudinal direction. I mention these circumstances merely to give it as my opinion 

 that the striated appearance was caused by the very elongated tubes of the ligneous 

 zone, and that the joints were simply transverse cracks. 



" A very singular result has been brought about by mineralisation in Mr. Witham's 

 specimen. A large portion of the radiated tissue has been destroyed ; what remains is 

 contained in a narrow marginal strip and in numerous isolated pea-shaped bodies, 

 imbedded in a crystalline matrix, and situated inwardly to the latter. The reader is 

 therefore requested to fill up in imagination all the vacant spaces which are represented 

 in figs. 2 and 3 of pi. iv, and with the same kind of tissue as that which forms the 

 marginal strip and the isolated bodies. To aid this a transverse restoration of the 

 vascular and ligneous system is given in fig. 1, which is a little above the natural size. 



*' Anabathra pulcherrima is undoubtedly a dicotyledonous plant. It possesses a 

 broad ligneous zone {a, fig. 1, pi. iv), a large medullary sheath in the shape of a hollow 

 cylinder {b), and apparently a large pith (c). The ligneous tissue consists of very much 

 elongated tubes which are occasionally quadrilateral, but generally hexagonal ; they are 

 arranged in radiating series, and are remarkably regular in diameter throughout the 

 thickness of the zone, till within the precincts of the vascular cylinder, where they 

 become considerably reduced. The apertures caused by sectionising these tubes are 

 distinctly seen with a common magnifier. Their length appears to be considerable, since 

 a longitudinal section nearly half an inch long shows none of the tubes with both 



