258 PROF. W. C. WILLIAMSON ON A NEW FORM 



instances these membranes can be traced continuonsly for 

 considerable distances round the several sporangia ; but in 

 other cases they seem to have been disturbed and broken up 

 by the swelling of the spores. I apprehend that this derange- 

 mentj combined with the regular symmetry and exquisite 

 preservation of the vasculo-cellular portions of the cone, 

 may be accepted as an indication that the spores had reached 

 maturity, rather than been in a half-developed state. In 

 all cases the undulating outlines of the sporangia indicate 

 the same thing, the membranes having been apparently 

 corrugated and shrivelled, their protective functions ha^dng 

 been nearly fulfilled. The exact number of the sporangia 

 clustered round each sporangiophore is not certain. I 

 have not been able to trace more than three in many 

 instances ; but occasionally I find indications of a fourth. 

 We may safely conclude from three to four to have been 

 the normal number associated with each sporangiophore. 

 I am unable also to make out accurately the posi- 

 tion and extent of the surfaces attaching the sporangia 

 to the sporangiophores. I have already pointed out the 

 distinctness of the sporangial membranes immediately be- 

 neath the external investing bracts on the left side of fig. 4. 

 The spores (figs. 11, 12) exist as a dense mass of separate 

 cells, packed closely together within the sporangia ; but 

 occasionally detached ones are imbedded in the translucent 

 carbonate of lime with which parts of the fossil are infil- 

 trated, so that their structure is not difficult to determine. 

 They consist of an outer [i) and an inner cell- wall {i'), the 

 latter obviously representing the primordial utricle of au- 

 thors and enclosing some peculiar cell-contents. In some 

 instances, as shown in fig. 12, these cell-contents are aggre- 

 gated into a dark well-defined central mass ; but in others, 

 as in fig. II, this mass has no defined outline, being gra- 

 dually merged in the inner cell-membrane (i') which en- 

 closes it, whilst occasionally it is absent. I was at first 



