1892.J Organisation of Fcssil Plants of the Coal-Measures. 469 



It will be seen that all the lines of Nova Anrigae have previously 

 been recorded in other NOVOD, or in the bright-line stars. 



The complete spectrum, including the photographic region, was 

 shown in the diagram exhibited on the screen. This, and the light 

 curve of the spectrum from F to C, was drawn by Mr. Fowler and 

 Mr. W. J. Lockyer, on February 22, and confirmed by Mr. Fowler on 

 February 23. The 3-foot reflector and McClean spectroscope were 

 employed in each case. 



The changes which are taking place in the Nova are exactly what 

 would be expected according to my hypothesis, that new stars are 

 produced by the collision of meteor-swarms. The rapid fading of 

 the star demonstrates that small masses and not large ones are en- 

 gaged, and this is further confirmed by the observed diminution in 

 the brightness of the continuous spectrum relatively to the bright 

 lines. If two condensed bodies were in collision, it is evident that 

 the lines would fade first. 



III. " On the Organisation of the Fossil Plants of the Coal- 

 Meaflures. Part XIX." By W. C. WILLIAMSON, LL.D., 

 F.R.S., Professor of Botany in the Owens College, Man- 

 chester. Received January 18, 1892. 



(Abstract.) 



The author recalls attention to the discovery by the late Rev. W. 

 Vernon Harcourt of a fragment of a Lepidodendroid branch, in which 

 the internal structures were well preserved. The specimen was 

 described and figured, first by Witham, who gave to it the well-known 

 name of Lepidodendron Harcourtii. It was next described by Lindley 

 and Hutton, in their 'Fossil Flora,' and still later, and more scientifi- 

 cally, by Brongniart, in his 'Vegetaux Fossiles.' In its interior 

 Brongniart found a single vascular cylinder encasing a medulla. At 

 a later period he obtained fragments of two other plants, in each 

 of which he found the above cylinder, but invested by a second one 

 which was obviously an exogenous product of a cambium zone. 

 From these three specimens he unfortunately concluded that the first 

 belonged to a Cryptogamic Lycopod, whilst the second and third were 

 Gymnospermous Phanerogams. These latter examples he further 

 identified with his genus Sigillaria. 



This classification was universally accepted by the palseobotanical 

 world until 1871, when, in his Memoir, Part II, the author announced 

 his conviction that Lepidodendra and SigillariaD were alike 

 Cryptogams, and that the exogenous zone supposed to be characteristic 

 of the Phanerogams was not confined, in ancient times, to that great 

 division of the vegetable kingdom. 



