Structure and Affinities of Fossil Plants f rom Palcvozoic Rocks. 117 



IV. "On the Eesult of Chilling Copper-Tin Alloys." By C. T. 



Heycock, F.R.S., and F. H. Neville, F.E.S. 

 V. " On the Theory of Consistence of Logical Class-frequencies, and 

 its Geometrical Representation." By G. Udny Yule. 



" On the Structure and Affinities of Fossil Plants from the 

 Palaeozoic Rocks. IV. The Seed-like Fructification of Lepido- 

 carpon, a Genus of Lycopodiaceous Cones from the Carbon- 

 iferous Formation." By D. H. Scott, M.A., Ph.D., F.R.S., 

 Hon. Keeper of the Jodrell Laboratory, Royal Gardens, Kew. 

 Received February 19, — Read February 28, 1901. 



(Abstract.) 



A short account of the new genus Lepidocarpon has been given in a 

 note communicated to the Royal Society last August* ; the present 

 paper contains a full, illustrated description of the fossils in question, 

 together with a discussion of their morphology and affinities. 



The strobilus of Lepidocarpon Lomaxi, the Coal-measure species, is, in 

 its earlier condition, in all respects that of a Lepidostrofais, of the 

 type of L. Oldha mills. 



In each megasporangium, however, a single megaspore or embryo- 

 sac alone came to perfection, filling almost the whole sporangial 

 cavity, but accompanied by the remains of its abortive sister-cells. 

 An integument ultimately grew up from the sporophyll, completely 

 enclosing the megasporangium, and leaving only a narrow slitdike 

 opening, or micropyle, along the top. As shown in specially favour- 

 able specimens, both of Lepidocarpon Lomaxi, and of L. tVildianum, 

 the more ancient Burntisland form, the functional megaspore became 

 filled by a large-celled prothallus, resembling that of the recent Isoetes 

 or Selaginella. The whole body, consisting of the sporophyll, bearing 

 the integumented megasporangium and its contents, became detached 

 from the strobilus, and in this isolated condition is identical with the 

 " seed " described by Williamson under the name of Cardiocarpon 

 ano malum, which, however, proves to be totally distinct from the 

 Corclaitean seed so named by Carruthers. 



The seed-like organs of Lepidocarpon are regarded by the author as 

 presenting close analogies with true seeds, but as differing too widely 

 from the seeds of any known Spermophyta to afford any proof of 

 affinity. The case appears rather to be one of parallel or convergent 

 development, and not to indicate any genetic connection between the 

 Lycopods and the Gymnosperms, or other Phanerogams. 



* " Note on the Occurrence of a Seed-like Fructification in certain Palaeozoic . 

 Lycopods," « Roy. Soc. Proc.,' vol. 67, p. 300. 



