22 The Royal Society, London. 



The strobilus is of the ordinary Lepidostrobus type. The 

 cylindrical axis bears numerous spirally disposed sporophylls, each 

 of which consists of a long horizontal pedicel, expanding at the 

 distal end into a rather thick lamina, which turns vertically 

 upwards. 



Anatomically, the structure is also that of a Lepidostrobus. 

 The stele which traverses the axis has a narrow ring of centri- 

 petal wood, and a large pith; the leaf-trace bundles which pass 

 out to the sporophylls are collateral in structure, and agree closely 

 with those described by Mr. Maslen in Lepidostrobus Oldhamius l ). 



The ligule is sometimes well preserved; it is seated in a de- 

 pression of the upper surface of the sporophyll, at the distal end 

 of the sporangium, and is thus in the normal position 2 ). 



With one exception, the speciraens of the strobilus are imma- 

 ture, and their tissues not quite fully differentiated. These younger 

 specimens bear sporangia which are essentially those of a Lepido- 

 strobus. A single large sporangium is seated on the upper surface 

 of the horizontal pedicel of each sporophyll, to the median line 

 of which it is attached along almost its whole length. 



The sporangium narrows out towards the top, and terminates 

 above in a well-marked ridge ; in general form it resembles Wil- 

 liamson's Cardiocarpon anomalum, but in the immature condition 

 there is no integument. The outer layer of the sporangial wall 

 has the columnar or palisade-like structure characteristic of Lepido- 

 strobus; it is lined by a more delicate inner layer, which may be 

 several cells thick. 



So far the structure is simply that of a Lepidostrobus with 

 rather thick-walled sporangia. 



Within the sporangial cavity, the membranes of the megaspores 

 are usually preserved; a single large megaspore almost fills the 

 sporangium, but smaller, abortive spores, with thicker walls, are 

 also present. Some specimens show that three of these abortive 

 spores were present in each sporangium. It appears, then, that a 

 single tetrad was developed in each megasporangium, and that of 

 the four sister-cells one only caroe to perfection, constituting the 

 functional megaspore. 



In one specimen, discovered by Mr. Wild, the strobilus is 

 in a more advanced condition. In its upper part the sporophylls 

 simply bear sporangia, as above described, but lower down in the 

 cone these are replaced by integumented, seed-like, structures, 

 identical with the detached bodies called Cardiocarpon anomalum 

 by Williamson. 



The structure of this strobilus is sufficiently well preserved to 

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

 mature specimens, and, as the tissues are more completely formed, 

 exhibits the Lepidostroboid characters even more clearly. 



*) Maslen, „The structure of Lepidostrobus". (Trans. Linn. Soc, Lon- 

 don. Ser. II Vol. V. 1899.) 



2 ) Malsen, „The ligule in Lepidostrobus". (Annais of Botany. Vol. XIL 

 1898.) 



