288 AN OTTOKAR TA-JjIKE PLAISTT FEOM SOUTH AFRICA, [vol. Ixxvii, 



platyspermic seed, originally produced in the cupule, but growing 

 out beyond it as it approaches ^latu^it3^ 



On this view the Indian Ottokaria would be regarded as a 

 similar structure, in which the seed had not yet matured. It seems 

 difficult, however, to press this interpretation, in view of the absence 

 of a clear line of demarcation between the head and the wing, 

 although it is conceivable that in the process of j)reservation this 

 demarcation may have become obliterated. 



David White records the presence of small oval bodies 1 to 

 l-2o mm. long and 5 mm. (? misprint for '5 mm.) wide on the 

 surface of his specimen : — ' in some cases a small round or oval 

 point was indistincth^ seen a little above the middle of these 

 impressions,' and ' the distal ends were a little wider.' 



These bodies were regarded as sporangia; but no spores were, 

 obtained from them. It is my opinion that the bodies so described 

 may have originated from the same structures as those that formed 

 the projections and humjDs of brown cells seen on the surface of 

 the specimen now described, though little comparison is useful 

 with White's figure (pi. vii, fig. 7 «). I think that there can be 

 hardly anj^ doubt that the projecting humps which I have 

 described were not sporangia, but rather of the nature of ornamen- 

 tations, and similar to the marginal projections seen in the Indian 

 and Brazilian specimens. 



Another explanation of the original nature of the wing presents 

 itself, owing to the continuity of the white material (altered plant- 

 tissue) from the wing to the head. This is the suggestion that the 

 wing was originally formed from a thin elliptical envelojDC which 

 ensheathed the head or cupule in this species, but was absent in the 

 Indian form. This thin sheath may have sprung from the base of 

 the head, and have extended some distance beyond it ; when being 

 flattened in preservation, it would assume the shape now possessed 

 by the wing. On this view the head may itsejf have been a seed 

 with a hard ornamented coat. 



There may be other possible interpretations ; but, until further 

 specimens are discovered, no hypothesis can be adduced which has 

 a very firm foundation. The suggested connexion with Glosso- 

 fteris is also very speculative ; so long, however, as the reproductive 

 structures of that plant remain unknown, the association of Otto- 

 karia with it in widely-separated localities is a fact which must be 

 kept in view. 



