The Fossil Plants of the Coal Measures. 123 



appear to belong. But there are others which have not 

 been identified with a corresponding degree of probabiHty. 



BB. — p. 16, Fig. 26A. Branch of a Lepidodendron, with a Lepidos- 

 trobus, b, still attached to its arrested lateral branch a'. The 

 Museum of the Owens College. 



BB. — p. 17, Fig. 27A. A Lepidostrobus attached to the extremity of 

 a long primary twig. Museum of the Owens College. 



BB. — p. 26, Figs. 53 and 54. Two Lepidostrobi in the British Museum. 



BB. — p. 27, Figs. 55 and 56. Lepidostrobi in the collection of the 

 British Museum. 



HOMOSPOROUS. 



BB. — p 27, Fig. 57. Lepidostrobus, C.N, 1614. 



BB. — p. 27, Fig. 58. Homosporous (?) Lepidostrobus, C.N. 56S, 



BB. — p. 27, Fig. 59. Centre of Fig- 58. Further enlarged, 



BB, — p. 27, Fig. 60. A bundle equivalent to a leaf-trace going to a 

 sporangiophore of Fig. 58. 



BB. — p. 27, Fig. 61. A partly tangential of the Strolsilus 58, C.N. 



574- 

 BB, — p. 28, Fig. 62. A restored vertical section of part of the Strobilus, 



Figs. 58 and 61. 



BB. — p. 28, Fig. 63. Transverse section of a fragment of a Heteio- 

 sporous Lepidostrobus, C.N. 587 A. 



BB. — p. 29, Fig, 64, An obliquely vertical section through a young 

 Strobilus, C.N, 577, 



THE SIGILLARIyE. 



Few types of fossil vegetation have been the subjects 

 of so many changes, and occasioned so much discussion, as 

 this one has done. At an early period the group appeared 

 to be a well-defined one, though opinions varied widely as to 

 the living plants they were supposed to represent. But 

 unfortunately a specimen which fell into the hands of 

 Brongniart became a veritable apple of discord. That 

 author had already described the Lepidodendron, which, as 

 mentioned on a previous page, had a medulla surrounded 

 by a primary vascular cylinder, and which feature he 

 regarded as typical of the Lepidodendra. In this newly- 

 acquired fragment of a Sigillaria he found this primary 

 tracheal cylinder surrounded by a secondary xylem strand. 

 He somewhat hastily concluded that the first of these two 

 J 



