340 
PROFESSOR W. WILLIAMSON ON THE ORGANIZATION 
important to record every step of advance in tire direction of unity of view. He says, 
“ the slice enclosed shows very well what I would call the most 'perfect kind of Lepido- 
dendron structure, and which, but for the better development of the woody cylinder 
in Sigillaria, comes very near, if not quite up to, the lowest type of the latter.” 
“ Your Lepidodendron is perfectly exogenous, and therefore enters into that general 
type which leads up to the highest plants.” “ As for me, I do not doubt the truly 
exogenous character of the stems of all Sigillarise, and some Lepidodendra, and that 
some of the forms approach very closely to each other.” * All the phenomena tend to 
confirm my previous conclusions that Lepidodendra and Sigillarise belong to the 
same type of vegetation ; that they are equally Cryptogamic plants, but that the 
Sigillarise represent, so far as then vegetative organs are concerned, the highest modifi- 
cation to which the Lycopodiaceous type has ever attained. 
Lepidodendroid Reproductive Organs. 
I some time ago discovered a few singular fringed macrospores, both in the Oldham 
and the Halifax beds. More recently both Mr. James Spencer, of Ackroyden, near 
Halifax, Mr. Binns, of Delph Hill, in the same district, and Mr. Earnshaw, of 
Oldham, have forwarded to me numerous examples of the same objects. We have 
not yet obtained these macrospores in union with the Lepidostrobus to which they have 
belonged, but it is most probable that one of two that I have received has been then 
parent strobilus. One of these is a crushed one, abounding in microspores. For this 
I am indebted to Mr. Binns ; both that indefatigable worker and Mr. Spencer have 
sent me sections of another one, which I shall describe in detail. The microspores 
of the former of these strobili display no peculiarities ; figs. 48 and 71, exhibit some of 
them enlarged 160 diameters. The second Lepidostrobus, on the contrary, is a very 
remarkable one. 
Fig 53 represents a slightly oblique transverse section of it from Mr. Binns’ cabinet. 
Fig. 54 is a slightly oblique tangential one, from Mr. Spencer’s Cabinet, made nearly 
in the plane of the outer surface of the common axis of the strobilus. Fig. 55 is also 
an obliquely tangential section which I have obtained from a fragment forwarded to me 
by Mr. Spencer. Fig. 56 is part of a nearly longitudinal section from the same frag- 
ment, and fig. 57 is the central sporangium of fig. 55 enlarged 75 diameters. The 
medullary tissues, as well as the innermost cortical layer, have disappeared from all 
these sections. In fig. 53, a large Stigmarian rootlet, x, has nearly filled the internal 
cavity thus left, pushing aside the vascular axis, a, which has been a cylinder con- 
sisting of unusually small barred vessels, each having a diameter of about 'OOl.t To 
facilitate reference to the figures the same letters are affixed to identical organs in all 
* In litera. April 11, 1877. 
t I liave recently received some fine transverse sections of tLis cylinder, the details of which will be 
described in a forthcoming memoir. June 10th, 1878. 
