Schimper and Mougeot. 407 



entirely united into a sheath, yet sheath-segments with vaiying 

 numbers of leaves are found. On the other hand, the leaves are 

 occasionally free to their bases. They are strap-like structures, 

 with smooth margins and a bundle of fine parallel nerves down 

 the centre. 



The stems from which the leaves had fallen previous to pre- 

 servation are of various types. They are known from impressions 

 and casts. The external surface may have been smooth or possibly 

 finely ribbed. The internal casts or impressions are finely ribbed. 

 There are, however, two types of these, and their interpretation 

 must remain ambiguous until we learn something from petri- 

 factions about the internal anatomy of these Mesozoic Equisetales. 

 We may, nevertheless, note that the libbing appears to be coarser 

 in the lower parts of the stem. 



On certain of the ribbed internal casts there are at the nodes 

 two kinds of prints: — the larger lie just above the nodal line and 

 are branch-scars, while the smaller ones probably represent leaf- 

 scars. 



The roots of 8. paradowa have been found, and closely resemble 

 those of Calamites {Pinnularia). It is doubtful whether the fructi- 

 fication has ever been discovered. 



The ribbed internal casts mentioned above sometimes encase 

 an innermost cylindrical cast. This is smooth, and probably 

 represents a cast of a partially hollow pith. Such a structure 

 has not been noticed before, though I found exactly the same 

 phenomenon in several examples of the so-called pith-cast of 

 Eqidsetites mougeoti, Schimper and Mougeot, from the Bunter of 

 the Vosges Mountains, which are preserved in the Strasburg 

 Museum. This plant is there associated in the same beds with 

 /S^. paradoxa. Though the smooth outer surface of E. mougeoti is 

 known, examples with leaves have never been described. The 

 pith-casts are indistinguishable from those of Schizoneura. Ac- 

 cordingly it becomes ever clearer that E. mougeoti is merely the 

 name given to large leafless stems of 8. paradoxa* . One point, 

 however, is not evident : the smooth external cast seen in E. 

 mougeoti has not, so far, been found at Bromsgrove. Yet the 

 external surface of the smaller branches is smooth, and we may 

 probably assume that the larger examples have still to be sought 

 for. 



How far the presence of this innermost cast can be taken as a 

 distinguishing mark of Schizoneura cannot be determined as yet, 

 until it has been observed or disproved in other species. 



* In this connection it may be noted that Seward [loc. cit. p. 88) figures 

 as Schizoneura, sp. a, a stem with smooth external surface enclosing a ribbed 

 pith-cast, similar to both E. mougeoti and S. paradoxa, and calls attention to the 

 resemblance of the whole fossil to the former. 



