384 
Palaeontologie. — Algae. 
by a sheath of transfusion tissue. The ligular pit is very long and 
narrow, and is placed just above the leaf scar. 
The branching takes place both by equal and unequal dichotomy. 
The stele branches in the latter manner. 
The Author discusses the application of the term Halonial to 
these branches, and does not consider that ‘Halonial’ branches are 
fructigerous. This stem is contrasted with L. Harcourtii , and com- 
pared with L. vascularis Binney. Arber (Cambridge). 
Weiss, F. E., The Parichnos in the Lepidodendraceae. (Mem. & 
Proc. Manchester Lit. & Phil. Soc., Vol. 51, Pt. II, N°. 8, p. 1—22 
with a plate, and 8 text-figures, 1907.) 
After reviewing briefly the present position of our knowledge 
of the parichnos of Lepidodendron and Sigillaria , the author demon- 
strates, in the former genus, the actual union of the parichnos Strand 
and the middle cortex (figured). He points out that in fossil Lyco- 
pods the normal mature condition of the parichnos is not an empty 
canal, as has been recently asserted, but a well preserved tissue. 
The function of this tissue is next discussed, and a summary 
of the more modern views on this subject is given. The author con- 
cludes that its function was respiratory. The parichnos Strand, con- 
necting as it does the delicate and lacunar tissue of the mid-cortex 
with the intercellular spaces of the leaf, consequently, through the 
intermediary of the Stomata, enables the inner living tissues of the 
stem to be supplied with the necessary oxygen. The parichnos 
Strands in Lepidophloios are not exposed on the surface of the leaf- 
base, but are covered in by the epidermal layer, which is provided 
with numerous Stomata. 
The Author next discusses the two very definite, oblong prints 
found in some Lepidodendrons just below the leaf-scar. These scars 
are formed by two patches of specialised cells, which are in com- 
munication with the parichnos. The cells are exceedingly small and 
stellate, and are separated by wide intercellular spaces. Their struc- 
ture is figured. They form an aerenchyma. At the surface of the 
leaf-base they were covered in by an epidermal layer provided 
with numerous Stomata. Figures are given of a reconstruction of the 
leaf-base of Lepidodendron , showing the relationship of the aeren¬ 
chyma to the parichnos. 
The paper concludes with a discussion on the Provision for 
respiration in the Underground stems of Lepidodendron and Sigillaria, 
especially Stigmaria and Xenophyton. Arber (Cambridge). 
Anonymus. Bureau du conseil international pour l’explora- 
tion de la mer. Bulletin trimestriel des resultats acquis 
pendant les croisieres periodiques et dans les periodes 
intermediaires. (Partie D. Annee 1905—06. N°. 4. Avril—Juin 
1906. Copenhague (A. Höst et fils). 1907, p. 95—126.) 
The bulletin published by the international Cooperation for the 
study of the sea contains as usually a large material of plankton- 
lists. The tables published in the present number treat of plankton 
collected in May 1906 from the following areas: 
1. Gulfs of Bothnia and Finland, North-Baltic Sea (deter- 
mined by W. M. Levander). 
