110 MEDULLOSEAE [CH. 



which, had we a fuller knowledge of them as complete individuals, 

 would be assigned to more than one generic type possessed 

 fronds simulating in habit those of certain Ferns with some of 

 the pinnae bearing seeds often of considerable size and in all 

 cases of complex structure, agreeing in many respects with those 

 of existing Cycads, while other fronds, or in some cases it may be 

 other pinnae, bore microsporangia similar in form to the sporangia 

 of Ferns. 



a. Microsporangia. 



Neuropteris. A. Neuropteris heterophylla 1 . 



Several examples of supposed fertile specimens of Neuropteris 

 are recorded in palaeobotanical literature, but it was not until 

 1887 that any satisfactory specimen was discovered. In that year 

 Kidston 2 described a specimen of Neuropteris heterophylla from 

 the Lower Coal Measures of Scotland in which slender forked 

 branchlets bear small bodies at their tips some of which appear 

 to represent four-valved organs (fig. 421, D), though the imperfect 

 state of preservation renders impossible any definite pronounce- 

 ment as to their structure. To the specimen are attached a few 

 sterile pinnules, showing that it is a portion of a frond of N. hetero- 

 phylla characterised by the substitution of reproductive organs 

 for pinnules. The subsequent discovery of seeds attached to 

 pinnae of the same species afforded strong presumptive evidence, 

 almost amounting to proof, of the microsporangial nature of the 

 Scotch specimen. For this specimen, although no precise diagnosis 

 is possible, Dr P. Bertrand 3 has proposed the generic name 

 Neurotheca. In 1911 the Abbe Carpentier 4 described some small 

 ovoid bodies, 1 1-5 mm. long, from the Coal Measures of France 

 arranged in groups of 4 to 6 and in some cases said to be borne 

 on a slender pedicel which he found in association with N. hetero- 

 phylla and compared with sporangia described by Lesquereux 

 from the Coal Measures of Arkansas as Sorocladus stellata 5 . These 

 supposed microsporangia have recently been assigned by Bertrand 6 

 to Sphenophyllum. 



1 Vol. ii. p. 568, fig. 371. 2 Kidston (87) B. 



3 Bertrand, P. (13) p. 117. 4 Carpentier (11) p. 10. 



5 Lesquereux (80) A. p. 328, PI. XLVIII. 6 Bertrand, P. (13) p. 120. 



