58 NATURAL SCIENCE. ,,^^ch. 



the Sigillavia gave rise to the Stigmavia, or vice versa ? To this 

 question, so far as I am aware, no satisfactory answer was given, 

 and its solution was left over until further investigations should 

 throw fresh light upon it. 



Some such light appears to have been obtained by Professor 

 Grand' Eury, who has recently written an elaborate memoir on the 

 Geologic et la Paleontologie du Bassin houillev du Card, in which the subject 

 is dealt with. Unfortunately, this memoir will only be accessible to 

 a very limited number of workers. Printed under the auspices of the 

 colliery companies of the district dealt with, only 125 copies have 

 been struck off, and these, it is understood, will not be obtainable by 

 purchase, but disposed of in another way. M. Zeiller, however, in 

 presenting, on behalf of the author, a copy of the memoir to the 

 Societe geologique de France, has given a careful and somewhat lengthy 

 summary of the palaeontological portion, and has thus ensured for 

 the main results a much wider publicity than they would otherwise 

 have obtained. So far as these bear upon the morphological 

 character of Stigmaria and its relation to the aerial stem of Sigillaria, 

 they are embodied in the following paragraphs, for the substance of 

 which I am indebted to M. Zeiller's excellent summary. 



In the first place, it may be noted that Professor Grand' Eury, like 

 Count Solms-Laubach, has come to the conclusion that Stigmaria are 

 rhizomes which floated in water or spread themselves out on the 

 surface of mud. In this condition they were able to live on in- 

 definitely without giving rise to an aerial stem. But his observa- 

 tions have led him much further than this, and have enabled him to 

 indicate, at least in a general way, the mode in which these creeping 

 rhizomes gave origin to aerial stems. The first step in the process is 

 the knotting up of the Stigmaria, so to speak, in order to form a large 

 bulb. M. Zeiller does not state whether this bulb-formation takes 

 place at the growing tip of Stigmaria or at some other point, or whether 

 both cases are possible. However this may be, the connection is 

 said to be of such a nature that the bulbs are united to the Stigmavia 

 by a vascular axis. At first, the bulbs present four swelhngs at the 

 base, but these afterwards elongate, and ultimately show the cruciate 

 disposition so often recorded as characteristic of the bases of the 

 stems of Sigillaria. At first, neither the upgrowing stem nor the root- 

 like branches carry any appendicular organs, and consequently their 

 surfaces are not marked with the usual characteristic scars. Thus the 

 lower part of the bulb, in developing and branching, takes the form of 

 Stigmaviopsis, while at the same time the stem begins to raise itself 

 vertically. At the base of the stems arising in this way, and which are 

 often swollen into the shape of a bottle, M. Grand' Eury has observed 

 neither true foliar scars nor any trace of a vascular bundle, but merely 

 a number of glands arranged in pairs. Thus, the base of the aerial stem 

 has the characters of the fossils known as Syringodendron, or rather 

 those properly so-called, viz., those of the type of Syr. altcrnans, which 



