102 



The Naturalist. 



Gymnosperms. Prof. Williamsou is altogether opposed to this 

 view, believing the Sigillaricd to be no less cryptogamic than the 

 Lepidodendra, and we believe the next part of his " Memoirs " will be 

 largely occupied with a demonstration of the truth of his conclusions 

 based upon a careful comparison of a somewhat large series of 

 specimens. In the descriptions under notice, however, there is 

 sufficient evidence to warrant a strong presumption that on this point 

 Prof. Williamson is in the right, inasmuch as they show that although 

 the Arran plants are of lepidodendroid affinities, they yet possess the 

 " cylindre ligneux," or, as Prof. Williamson terms it, the " exogenous 

 zone," which, in the opinion of the French savants, is characteristic of 

 fossil gymnosperms. The evidence derived from the fossil fruits met 

 with in company with these stems, points likewise to their lepido- 

 dendroid nature. These are all true Lepidostrohi, though of probably 

 distinct species, containing both macrospores and microspores, some 

 of which, in one or two instances, are preserved. 



The Arran plants disposed of, the author next adverts to the stem 

 of Ulodendron, and certain spores and conceptacles described in his 

 previous memoirs, on which additional light has been thrown by the 

 examination of further specimens. He also gives descriptions of two 

 new fern stems, supplied by Messrs. Binns and Spencer, of Halifax, 

 of whose industry and patience in unearthing fossil plants and 

 preparing them for microscopic investigation it is impossible to speak 

 too highly. In this connection he returns to the discussion on the 

 nature of Traquarics, on which there has been considerable difference 

 of opinion between him and some other naturalists. Thus, Mr. 

 Carruthers, who early called attention to the objects so-called, came to 

 the conclusion that they were animal in their nature, and were, in fact, 

 carboniferous liadiolarians. Prof. Williamson, on the other hand, has 

 for some years maintained their vegetable origin, and has lost no 

 opportunity of becoming further acquainted with them, in the hope of 

 obtaining decisive evidence of their character. This he appears to 

 have now done, and the elaborate descriptions here given of the more 

 characteristic individual specimens will leave little doubt in the mind 

 of the student that their supposed animal origin is disposed of for ever. 

 It may be added that he is supported in his opinion of their vegetable 

 origin by Professors Haeckel and Strasburger, of Jena, the latter of 

 whom, adopting Prof. Williamson's diagnosis that they are crypto- 

 gamic macrospores, suggests that their nearest allies will possibly be 

 found in those of Azolla and other Ehizocarpous genera. 



Passing from these objects, the author devotes a few paragraphs to 



