Palaeontologie. — Algae. 
355 
discharged into a internal water-chamber upon which the archegonia 
abutted, the male cells are carried through soft tissues to the egg in 
a plastic tube. 
The other cause that must have played a prominent part in the 
simplification of the seed was the association with it of other struc- 
tures which relieved it of a part of the original load of duties that 
feil to its lot. The Angiospermic ovary provides the best example of 
a special organ inclosing the seed or ovule, affording it protection 
during the immature stages and also collecting the pollen. 
The history of the seed, as read from the imperfect and frag- 
mentary data that are available, has been a series of advances 
spread over long geological periods. The possibilities of the seed- 
habit were realised only bit by bit, and the high efficiency of the 
modern seed depends in large degree upon the close association of 
other structures which co-operate in its functions. No doubt the first 
Step, the retention of the megaspore, was the most important of 
all; though, that this might be effective, some contrivance for the 
capture of the pollen-grains must have accompanied it. Later Steps 
in the process of seed-evolution would include the adjustment of an 
intraseminal embryonic stage, and in time the Substitution of the 
pollen-tube for the liberation of sperms. 
Now assuming, that seeds have come into existence along some 
such lines, there is a great difficulty in conceiving the process other 
than discontinuous. Every one of the stages emphasised involves 
the conception of something more abrupt than mere gradual varia- 
tions. And there is, of course, the old difficulty as to how the 
organ or mechanism came to be preserved at its inception. All 
these difficulties vanish when it is recognised that effective Variation 
is of the discontinuous Order, and that the successive changes in- 
volved may be considerable enough to be designated jumps. 
Arber (Cambridge). 
Solorrano, M. M. and B. Hobson. Plant-remai ns. in Basalt, 
Mexico. (Geol. Mag. Dec. 5. Vol. IV. p. 217—19 and a plate. 1907.) 
The specimen figured is described as a piece of basaltic lava 
containing remains of Maize, and is in the Museo Michoacano, 
Morelia, Mexico. The impressions of female ears of Maize, and 
also entire grains and carbonized remains of the axis of the ear, 
are numerous and very distinct. Previous records of plant remains 
preserved in basalts are instanced. Arber (Cambridge). 
Anonymus. (Bureau du conseil international pour l’explo- 
ration de la mer): Bulletin trimestriel des rdsultats acquis 
pendant les croisieres periodiques et dans les periodes in- 
termediaires. Partie D. Annee 1906—1907. N°. 1—S.Juillet 
1906 — mars 1907. (Copenhague (A. Höst et fils). p. 1—95. 
1907—1908.) 
The publication of the large material of plankton collected du¬ 
ring the cruises of the international Cooperation for the study of 
the sea has been continued in the usual manner in these numbers 
of the bulletin. 
The present numbers contain plankton tables from: 
1. Gulf of Finland, August, Novemb., Febr. (determined by 
K. M. Levander). 
