1892. 



RELA TIONSHIP OF SIGILLARIA AND STIGMARIA . 59 



M. Grand' Eury now regards, not as decorticated Sigillariw, but the 

 part of the stem which stood in the water or mud, and was destitute 

 of leaves. This part, according to circumstances, might remain short 

 or attain a height of several metres. Higher up the trunk, the leaves 

 made their appearance, but the iirst to be developed were very short, 

 and were perhaps rather of the nature of scales. 



In this account of the development of Sigillavia with its Stig- 

 marian rhizomes, there are obviously many lacunae, which may be 

 due to the condensation necessary in M. Zeiller's paper. Nothing is 

 said, for instance, of the fate of the Stigmavia when the bulb formed 

 upon it has developed into a Sigillavia. This is certain to attract the 

 attention of palaeophytologists, and the more so since, in the stumps 

 of Sigillaria described in the literature, no trace of such a structure is 

 met with. The four primary rhizomes seen from below have merely 

 a cruciate depression between them, and show no signs of having 

 been attached to a parent Stigmavia. On the other hand, the absence 

 of such signs is capable of an easy explanation, and appears to 

 afford no substantial ground for rejecting the views put forward by 

 M. Grand' Eury. 



Subject, then, to the needful reservations, it will probably be 

 conceded that the mode of development of Sigillavia, as outlined 

 above, is not an unlikely one, and would be more or less consistent 

 with what has long been known of the relations of Sigillavia and 

 Stigmavia. It will be observed that the account furnishes a more 

 definite conception than has hitherto been possible of the nature of 

 the fossils known as Stigmaviopsis and Syvingodendron, and makes more 

 precise the distinction between the former and Stigmavia proper. 

 That distinction has not hitherto been received with much favour by 

 palaeophytologists generally, but M. Grand' Eury appears to be con- 

 vinced of its reality. As this conclusion is based upon observations 

 of wide extent — what are termed forests of fossil Sigillavia having 

 been opened out in the district investigated — it is, no doubt, entitled 

 to, and will receive, the respectful attention of other authorities. 

 Still, it may be pointed out that in several examples figured or 

 described in the literature, there is no absence of the characteristic 

 scars, even at the proximal ends of the four primary Stigmarian 

 branches into which Sigillavia divides at the base. This being so, 

 the possibility is suggested that the Stigmaviopsis stage may not be a 

 constant feature of the development of Stigmavia, but may be in some 

 way dependent upon circumstances, as appears to be the case with 

 the height of the Syringodendroid part of the Sigillarian stem. 



Thomas Hick. 



