Palaeontologie. 
383 
siles appelees Psavonius, Psaroniocaulon, Cauloptevis . (C. R. Acad. 
Sc. Paris. CXLV. p. 955-957. 29 Nov. 1907.) 
L’auteur rappelle que si les tiges de Foug£res houilleres con- 
nues sous les noms de Psaronius et de Cauloptevis presentent, dans 
leur structure et dans celle de leurs racines, les earacteres des 
Marattiac^es, il semblait qu’il y eüt entre elles et ces dernieres des 
diffdrences assez notables, en ce qui regarde la disposition de l’ap- 
pareil vasculaire. 
Or il a reconnu, dans les rachis secondaires d 'Angioptevis evecta, 
des variations successives par suite desquelles les faisceaux, d’abord 
repartis, en section transversale, suivant deux cercles places ä l’in- 
terieur l’un de l’autre, forment ensuite un cercle accompagne ä l’in- 
terieur d’une simple bande transversale presque rectiligne; plus loin 
cette bande s’unit ä la partie superieure du cercle externe formant 
un faisceau en forme d’X; ces dispositions sont ainsi conformes ä 
celles que presentent les bandes vasculaires des cicatrices des Cau¬ 
loptevis, du Caul. vavians Zeiller notamment. 
M. Pelourde a constatd en outre que le nombre des faisceaux 
va en se reduisant ä mesure qu’on s’eleve, et que finalement, la 
nervure mediane des pinnules d 'Aug. evecta ne possede plus qu’un 
seul faisceau, en forme d’arc ouvert ä la partie superieure et ä bords 
recourbes en dedans, conformement ä ce qui a lieu dans les der¬ 
nieres ramifications des rachis des Pecoptevis, lesquels representent, 
comme on sait, les frondes des Cauloptevis et des Psavonices. 
R. Zeiller. 
Watson, D. M. S., On a confusion of two species (. Lepidoden- 
dvon Havcouvtii Witham and L. Hickii Sp. nov.) under Lepi- 
dodendvon Havcouvtii Witham, in Williamson’s XIX Memoir; 
with a description of L. Hickii sp. nov. (Mem. & Proc. Man¬ 
chester Lit. & Phil. Soc. Vol. LI, Pt. 3, N°. 13, 24 pp., with 3 
plates and a text-figure, 1907.) 
The Author shows that the specimens figured by Williamson 
in 1893, under the name Lepidodendvon Havcouvtii Witham, were 
not identical with that species, but are a new and distinct type 
which the Author terms L. Hickii sp. nova. After a survey of W i 1- 
liamson’s memoir, the author passes to a detailed description of 
the new species. The pith is well marked, and in the larger branches 
shows evidence of meristematic activity on the outer margin. Isolated 
tracheids may occasionally occur in this region. The wood, which 
presents an unusually even contour, is small in amount. The pro- 
toxylem-points consist of small groups of scalariform tracheids of 
even diameter, with vertical threads between the bars. Outside the 
wood, a tissue, regarded as phlöem, occurs. The middle cortex is 
composed of large parenchymatous cells which appear to have 
formed a spongy mass with large air spaces. The outer cortex is 
a firmer tissue composed of smaller, thicker-walled cells. The phel- 
logen is very erratic in its development, and gives rise to a peri- 
derm, often of some thickness. The whole of each protoxylem-group 
of the stele apparently bent outwards and became the leaf trace 
which is mesarch when it leaves the stele. 
The leaf scar is situated at the apex of a cushion. This cushion 
has the form of a truncated rhombic pyramid. The bündle which is 
collateral, enters the leaf base almost horizontally, and is surrounded 
