144 Transactions of the Society. 



In connection with the fossils just described, we may recall 

 the old observation of Stur* that Sphenopteris Stangeri, a species 

 scarcely distinguishable from the foliage of Lyginodcndron old- 

 hamium, possessed fertile fronds with a naked rachis bearing 

 cupule-like organs ; these may either have once contained the seeds, 

 as in our species, or may have enveloped the unknown pollen-sacs. 



From the evidence afforded by Lyginodendron and supported 

 by the other cases mentioned, the conclusion must be drawn that 

 in certain species with the foliage of Sphenopteris the fructification 

 was not that of a Fern but of a seed-plant with Gymnospermous 

 affinities. 



In other species of Sphenopteris (S. elegans, S. Li?ikii, S. dissecta) 

 we know that the stem on which the fronds were borne was a 

 Heterangium ; this type of stem, occurring in a petrified condition, 

 has been thoroughly investigated anatomically, and has so much 

 in common with the structure of Lyginodcndron as to leave no 

 doubt of its near affinity with that genus. 



On the whole of the evidence, then, we find that under the 

 name Sphenopteris a heterogeneous assemblage is collected, includ- 

 ing a certain number of true Ferns, as shown by their fructification, 

 but including also a considerable group of plants which had 

 already entered the ranks of the Spermophyta. 



We will now pass on to a different family — that of the Neur- 

 opteridese, including Ncuroptcris, Alcthopteris, Odontoptcris and 

 other genera, among which are many of the most familiar " Fern- 

 fronds " of the Coal flora. From the work of the late illustrious 

 paheobotanist, M. B. Renault, of Paris, we know that the fronds of 

 both Alcthopteris and Ncuroptcris belonged to the petioles named 

 Mycloxylon, which are often found in the petrified state, and show 

 a structure remarkably like that of the leaf-stalk of a Cycad. 



* " Culmflora," Abhandl. d. K.K. Geol. Reiclisanstalt. Bd. viii. 1875-7. 



EXPLANATION OF PLATE III. 



Fig. 5. Trigonocarpon olivseforme. Longitudinal section of seed, s, s, fleshy outer 

 layer of testa ; e, inner hard layer of the same ; m, ruicropyle : inside 

 the seed the outlines of the contracted uucellus and of the embryo-sac can 

 be traced, x nearly 4 diam. Scott Collection, 040. From a photograph 

 by Mr. L. A. Boodle. 



., 6. T. olivx forme. Transverse section of seed, showing the twelve angles of the 

 testa, of which three are more prominent than the rest, s, e, the two 

 layers of the testa, as in fig. 5. The outlines of the uucellus and embryo- 

 sac are distinct, x nearly 4 diam. Scott Collection, 325. Hough Hill, 

 Lower Coal Measures. From a photograph by Mr. L. A. Boodle. 



„ 7. Section of an annulate Fern-Sporangium containing spores, a, annulus con- 

 sisting of enlarged cells, with rather thick walls. On the opposite side of 

 the sporangium the cells are much narrower, with thiuner walls, x about 

 80 diam. Dulesgate, Lower Coal Measures. From a photograph by 

 Mr. L. A. Boodle. 



