BIBLIOGRAPHY. 



121 



Museum of the Jardin des Plantes, it appears to me that the learned author's description 

 of the specimen, as well as the figure in the plate, are both remarkably correct. 

 Although his specimen does not show the external structure of large Sigillarice, my 

 own observations lead me to the conclusion that we shall find the latter very much 

 resembling, if not altogether identical in structure with, Sigillaria elegans. In large 

 specimens of S. reniformis and S. orcjanum, whose structure is preserved in my own 

 cabinet, there is distinct evidence of the internal cortical envelope, formed of elongated 

 cellular tissue, or utricles, and disposed in radiating series, in all respects like that 

 described by M. Brongniart in his Autun specimen. 



" The longitudinal and tangential sections of my specimen show that the vessels of 

 the central axis and the woody cylinder are barred transversely on all their sides. M. 

 Brongniart found this to be the case with Sigillaria, and gives it as characteristic 

 of Sigillaria, Stigmaria, and Anabathra} Specimens of these three, now in my cabinet, 

 clearly prove that their central axes and their woody cylinders are exactly the same in 

 structure and arrangement ; thus affording evidence, from structure, that Stigmaria is the 

 TOot of Sigillaria, and that AnahatJtra is a Sigillaria — which has long been expected 

 "would prove to be the case." 



24. BiNNEi" {DiploxT/Ion) -. — "This specimen [No. 1] is not in so perfect a state of 

 preservation as those fossil woods intended to be hereinafter described in this communi- 

 cation, especially as regards its central and external parts ; but it certainly differs from 

 them in having a larger mass of scalariforifi tissue composing the central axis, and 

 having the inner portion of the wedge-shaped bundles forming the internal radiating 

 cylinder of a convex shape as they approach the central axis, somewhat like those 

 represented by Brongniart in his Sigillaria elegans, and still more resembling those 

 described by Corda in Biploxylon cycado'ideum ; but my specimen shows within those 

 convex bundles a broad zone of scalariform tissue, arranged without order, and marked 

 with transverse striae. 



" It has been assumed, both by Corda and Brongniart, that Diploxylon had a pith 

 composed of cellular tissue, surrounded by a medullary sheath of hexagonal vessels, 

 arranged without order, barred on all their sides with transverse striae. My specimen is 

 evidently more complete in structure than those of the last-mentioned authors, or even 

 that which AVitham himself described ; but, although it shows the so-called medullary 

 sheath in a very perfect state, there is nothing to indicate the former existence of a pith 

 of cellular tissue. All the specimens examined by Witham, Corda, and Brongniart 

 appear to have had their central axes removed altogether, and replaced by mineral 

 matter, or else only showing slight traces of their structure ; and these authors appear to 

 have inferred the former existence of a pith of cellular tissue, rather than to have had 

 any direct evidence of it in the specimens of Anabathra, Diploxylon, and Siyillaria 



1 " • Extrait des Archives du Museum d'Histoire Naturelle,' p. 429, Paris, 1839." 



2 'Phil. Transactions,' vol. 155, p. 583, 18G5. 



IS 



