PALAEOZOIC CONE-GENUS LEPIDOSTEOBrS. 



225 



The great interest of the anatomy of the cone axis of this species lies in the variations 

 in structure which arise as the apex is approached. This point will be dealt with more 

 fully in Section 5 of the present paper (see pp. 228-230 and Text-fig. 4). 



(4) The Sjporophyll Traces in the Axis. 



Numerous sporophyll traces are visible in the transverse sections. In one case * 

 have counted about 50. The xylem of these traces is fairly massive ; immediately after 



I 



Tezt-fig. 2 



I.C&.. 



0.C 



,-xy 



B 



C 



WiD 



A. SporophvU trace in middle cortex, from a transverse section of the cone axis. Watson 



Coll., A. 94. 



) 



B 



axis. Watson Coll., 



A. 93. (x318). 



(a'v.= xylem ; i.c.s. 



inner cortical sheath ; o.e. = outer cortex.) 



C. A tetrad of spores and two single spores, one of which shows the triradiate marking 

 and the other the equatorial border, U. C. L. CoU., C. 16. k (X 318.) 



ing the central cylinder it consists of 14 to 19 tracheides 



As usual, the bundl 



acquire a sheath of delicate tissue in passing through 



of sporophyll trace and sheath while in the middle cortical space 



Traces from the middle and outer cortical regions respectively arc shown in Text-fi 



the inner cortex. The diameter 



is 015 to 018 mm. 



2 



A & B. Near the cone apex the inner cortex 

 quence the sporophyll traces possess no sheath 



longer differentiated, and 



IT. c. L. CoU., 0. 16. i. 



