134 Transactions of the Society. 



B. Gihsonianus, and dther species, the external appearance of the 

 stem was similar to that of many recent Cycads, its surface 

 being completely invested by an armour of persistent leaf-bases. 

 Anatomically, there is also a marked agreement, the chief distinc- 

 tion consisting in the simpler course, in the case of the fossil, of 

 the vascular strands which pass out from the stem into the leaves. 

 A striking feature is the presence, in great numbers, on the leaf- 

 base and bracts, of flat, scaly hairs, of the same nature as the ramenta 

 characteristic of Ferns (plate VII. fig. 2, B). Even in external ap- 

 pearance, however, a Bennettitean stem, if in the fruiting condition, 

 differs conspicuously from that of any recent Cycad, in the presence 

 of a number of short, lateral branches, like large buds, wedged in 

 between the leaf-bases, and arising in their axils (see plate VI. 

 fig. 1, from an American species). These bodies are the fructifica- 

 tions, the characteristic feature of the l)ennettitepe. In structure, 

 as well as in position, they differ totally from any form of fructifi- 

 cation met with in recent Cycads or other Gymnosperms. The 

 short peduncle has the same anatomical structure as the main 

 stem, on a small scale ; it is remarkable, however, for the great 

 <levelopment of the phloem, which much exceeds the wood in 

 thickness. This unusual condition may be due to the fact that the 

 crowded reproductive organs, and ultimately the seeds, made a great 

 demand on the food supply, of nitrogenous and other assimilated 

 material, which it is the special function of the phloem to convey. 

 The peduncle bears many spirally-arranged l3racts, which com- 

 pletely inclose the fructification (see diagram, plate VII. fig. 2, A), 

 The end of this peduncle expands into a convex receptacle, on 

 which organs of two kinds are borne — the one fertile, the other 

 .sterile. The fertile appendages consist each of a long, slender 

 pedicel, terminating in a single orthotropous seed, with the micro- 

 pyle directed outwards. The seed- bearing pedicels are present 

 in large numbers ; the sterile appendages, or interseminal scales, 

 are still more numerous. They form a dense packing between the 

 seed-pedicels, and somewhat overtop the seeds themselv^es, expand- 

 ing at their apices to form an almost continuous envelope, leaving 

 only small perforations, into which the raicropylar ends of the 

 seeds are fitted. Towards the Imse of the receptacle the sterile 

 scales are alone present (see diagram, plate VII. fig. 2, A). They 

 form collectively a kind of pericarp, differing, however, from that 

 of an angiospermous fruit in the presence of openings for the 

 micropyles of the seeds. Both seed-pedicels and interseminal 

 scales are each traversed by a single vascular strand, which in the 

 former case terminates at the base of the seed itself. The whole 

 complex fruit is enclosed in the mantle of overlapping bracts. In 

 Bennettites Gihsonianus the fruits discovered are practically ripe, 

 for each seed contains a large, dicotyledonous embryo, with some- 

 what fleshy cotyledons (see plate VII. fig. 3). The embryo almost 



