of the Fossil Plants of the genus Sigillaria. 283 



be seen, that, in the latter species, we have but a slight modificatioB of 

 this character, and that we are, to all appearance, among the Ferns :♦ 

 on the other hand, if we compare it with the veining of the leaflets 

 «f Palceozamta pecten,f as represented twice the natural size in figure 

 8, PI. v., it cannot be concealed, that, in the latter, we have a modi- 

 fication equally slight, and that we hare before us » lorm essentially 

 that of a Cycas. 



Respecting the allied genera Ptevophyllum, Ctems, and some others, ii 

 is unnecessary to enter into any particulars, as their situation in the same 

 division of the vegetable kingdom is not improbable. 



Notwithstanding the view involved in the foregoing observations, I 

 wish it to be understood, that it is not my decided opinion that the genua 

 Otopteris is the form by means of which the passage from the Ferns to the 

 Cycases was effected. The presence of Pterophyllum in rocks belonging' 

 to an earlier age than is usually assigned to the true Otopterides, would 

 almost confirm the notion, that the Cycadeous type was directly related 

 with the Odontopteroid Ferns. With the exception of its probably being 

 bipinnate,J Odontopteris obtusa (Brong.), a coal-measure plant, does nat 

 appear to differ much from some species of Pterophyllum. Nor would I 

 be in the least surprised, if true Cycadeous remains were hereafter to be 

 ft)und in rocks of the same age as those of the North of England coal- 

 field ; even in this case, the view that has been taken would not be dis- 

 proved, unless it were shewn that remains of this kind occurred in 

 formations older than our coal-formation, and deposited during a period 

 in which the Ferns had not been called into existence. In the preceding 

 arguments, I have not been so anxious to establish the true connecting 

 link between two great classes of the vegetable kingdom, but rather to 

 shew, as far as leaves may be taken as guides, that certain fossils of this 

 kind possess characters which insensibly lead us from the Ferns to the 

 Cycases. Having, I trust, established this point, there still remains for 



• Although Otopteris is here called a Fern, I am equally disposed to look 

 upon it as a Cycas. 



t Vid4 Supplementary Note. 



I As regards the diflference between Ferns and Cycases in the divisions of thoir^ 

 leaves, I may state, that this difference does not appear to be of much importance. 

 I can offer no example of a cycadeous leaf being bipinnate, nor do I know of 

 any shewing a tendency to this character; nevertheless, suppose a leaf were dis- 

 covered bipinnate, and Cycadeous in other respects, I think we ought to pause 

 before placing it among the Ferns. The same may be urged with reference to 

 finding a simple leaf displaying a Cycadeous character: and as an instance in 

 point of the unwillingness (as it may be termed) of some Cycadeous leaves to leave 

 the simple form, I may refer to Pterophyllum minus, which shews its terminai 

 portion undivided to a considerable extent, — often a great irregularity in its 

 divisions, — and occasionally the latter extending only half-way to the rachis. Mr 

 Bean possesses a specimen of an entire leaf, about four inches in length, which 

 he considers of this species : it has only one divisioa on one sdde of the rachis, 

 or midrib, and two on the otlMr. 



