Id. I . II. Scott. Xi>f,- un fhc O'ri'fi-citci of n 



The structure of this strobilus is sufficiently well preserved to show 

 that the anatomy of the axis agrees with that of the less mature 

 IIMIS, and, as the tissues are more completely formed, exhibits 

 the Lepidostroboid characters even more clearly. 



M . Wild's specimen, then, demonstrates that the r,, /,//., ,,y,,,// 

 iiii'tiiKiliiiii of Williamson was borne on a cone with all the characters 

 of a Is-jtiil>i.-<fr<>Ii>i* t and that it represents the matured condition of the 

 -poran^ium and sporophyll. 



The detailed comparison of specimens in the young and the mature 

 condition has shown the nature of the change, which converts the 

 megasporangium, together with its sporophyll, into a seed-like organ. 

 The nucellus of the latter retains almost unaltered the structure of the 

 megasporangial wall, with its columnar layer. In the sporangial 

 cavity the single large megaspore, accompanied by its abortive sister- 

 cells, is present as before. A thick integument has, however, grown 

 up from the sporophyll, completely overarching the megasporangium, 

 except for a narrow crevice left open at the top. When seen in a 

 section tangential to the strobilus as a whole, this crevice is cut across, 

 and presents exactly the appearance of a micropyle; in reality it 

 differs from a micropyle in being a narrow slit, extending almost the 

 whole length of the sporangium, in the radial .direction, whereas the 

 micropyle of an ordinanr seed is a more or less tubular passage. 



The integument springs from the upper surface of the sporophyll- 

 pedicel ; it does not consist of the incurved margin of the pedicel, for, 

 in the more distal region, the margin of the latter projects consider- 

 ably beyond the insertion of the integument. 



From the frequency of detached specimens in the Cardiocarpan con- 

 dition, it appears that in nature the sporophyll, bearing the integu- 

 mented megasporangium, was shed as a whole, though parts of the 

 sporophyll-lamina no doubt perished, only so much being persistent 

 as was necessary to form a complete envelope to the " seed." 



In a strobilus associated with the seed-like specimens, and bearing 

 microsporangia, it was found that the latter, like the megasporangia of 

 the female cone, are provided with integuments. This specimen was 

 figured by Mr. Maslen as a variety of Lepitlostrobu* OUfonwM,* though 

 possibly deserving specific rank, a determination with which I agreed 

 at the time. There is every reason, however, to suppose that this 

 strobilus was a male fructification of the same species, the female of 

 which bears the integumented seed-like megasporangia above described. 

 The microsporangial integument is more widely open than that of the 

 megasporangium. 



The Burntisland specimens, which from their horizon are presumably 

 of a distinct species, are at present only known in the isolated Cunli'- 

 condition. They are of interest for two reasons : in one speci- 

 * MnsU-n, ' Structure of LepMost robu*,' p. 371, Plate 37, fig. 21. 



