LYCOPODIALES— LEPIDODENDEEJ5— OMPHALOPHLOIOS. 229 



depends on the relation of the oval Ijoss to the transverse scars, which I have 

 designated as leaf cicatrices, and these relations can perhaps be ascertained 

 only by the discovery of additional mateiial. On those bolsters the cortical 

 tissue of Avhich appears best preserved and intact the rim of the oval boss 

 would seem in some cases, as shown in the photograph, PL LXVIII, Fig. 1, to 

 be nearly but not quite tangential to the transverse scar, the punctiform trace 

 being slightly within the outer oval boundary. In this matter the evidence 

 of other bolsters would, however, seem somewhat conflicting. It should be 

 remarked that in those bolsters in which the base of the oval is most clearly 

 defined the vertical diameter of the transverse, or leaf, scar seems consider- 

 ably foreshortened in the course of fossilization. It is quite possible that 

 better or uncompressed inaterial will show a confluence of the oval rim Avith 

 the transverse scar, in which case the punctiform trace may represent some 

 expression or development of the vascular strand of the leaf. 



If it be found, as seems to be indicated in some instances, especially 

 where the protruding leaf scar is abraded, that the rim of the oval boss is 

 really in union by a narrow connection with what is here, perhaps errone- 

 ously, interpreted as the leaf scar, the conditions will be perhaps best 

 satisfied by assuming that the oval boss was the seat of some expansion or 

 unfamiliar structure on the ventral surface at the base of the leaf, of which 

 it would form a part. In such an arrangement the trace above the large 

 boss might be the homologue of the so-called "ligule" scar, while the small 

 umbilicate trace in the central depression would constitute a new basis for 

 speculative analogy. However, while far from conclusive, the signs at 

 hand appear to point to a lack of such a union. In either case,. assuming 

 that I am not mistaken in treating the transverse basal scar as proper to 

 the leaf rather than as a mere fracture or abrasion, we would seem to have 

 a cortex marked by prominently bossed Lepidodendroid bolsters, in the 

 axils of whose leaves was situated either some organ or appendage attached 

 to the oval boss, or else, as appeai-s more probable, an oval plaque in the 

 depression of which was a minute umbiHcate trace, the purpose of which is 

 unknown. In accordance with such an hypothesis the punctiform trace near 

 the ujDper edge of the main boss might be homologized with the upper append- 

 age trace or pit of the typical Lepidodendron, while the minute trace close 

 above the base of the leaf, if it proves to be distinct from the latter, may be 

 analogous to if not homologous with the so-called "ligular pit" in those stems. 



