44 MR ROBERT KIDSTON ON 



diameter ; but, as far as I am aware, these measurements are not derived from 

 GoLDENBERG's original specimens, but from his figures, which one can scarcely regard 

 as a reliable source for such minute measurements. 



Although microspores have not yet been observed in the cones of Sigillaria, it does 

 not follow that they are isosporous ; for the minute size of microspores, either in recent 

 or fossil Lycopods, would make their detection with certainty very difficult in the only 

 state of preservation in which the Sigillarian cones are known to us. 



Zeiller further suggests that perhaps certain cones bore macrospores, others micro- 

 spores, which may account for the absence of spores between the bracts of his Sigillaria 

 nobilis.* This condition in the case of Sigillariostrobus nobilis may be equally 

 explained, and I think more probably, by the state of maturity at which the cone had 

 arrived before mineralisation took place : the spores might have been shed at maturity 

 or been imperfectly developed. Several of my specimens show no indications of macro- 

 spores. This, of course, is only a suggestion, but it is equally valid to supposing the 

 cone contained only microspores. From certain appearances presented by a small 

 fragment of a Sigillarian cone from the Kilmarnock Coal Field, I am inclined to think 

 that the cones of Sigillaria were heterosporous, though I cannot speak definitely on 

 this point, but on a subsequent page I give the evidence on which I have formed this 

 opinion. 



Mons. Zeiller refigures and describes the specimens to which reference has already 

 been made in his complete work on the Carboniferous Flora of the Valenciennes Coal 

 Field,t and adds there the figure and description of another species, the Sigillariostro- 

 bus Crepini.\ 



In this the bracts are arranged on the axis in a gentle spiral, or are verticillate. This 

 character does not yet appear to be clearly determined. In form the bracts are elongate 

 rhomboidal, and divided into a limb and claw. The claw portion of the bract bends 

 downwards, but the limb is directed upwards ; thus a knee-like angle is formed where 

 the limb and the claw of the bract merge together. The margins of the bract are bent 

 up on each side of the medial nerve, and form a sort of sack or spoon-like structure ; 

 this is sometimes empty, but is occasionally occupied by an ovoid body. Mons. Zeiller 

 suggests that these ovoid bodies may be microspore sporangia. They are too large to be 

 macrospores, and had they been sporangia containing such, the probability is that some 

 of the remains of the macrospores would have been preserved. These "ovoid bodies" 

 are further said to be more or less enveloped by the bract which bears them ; frequently 

 only their edge can be seen, and their margins are often imperfect on account of portions 

 <»f the structure, which appears to have been very delicate, having adhered to or been 

 imbedded in the matrix. 



* Lor. rit., p. 267, pi. xii. figs. 1, 2, 2a. 



+ Etudes des Gites Mineraux de la France, Bassin houiller de Valenciennes. Flore fossile du Bassin houiller de Valen- 

 "'• irncs, Paris, plates i.-xciv., 1886, text, 1888. 

 J Ibid., p. 60r>, pi. Ixxvii. figs. 2-3. 



