262 Chronicles of Science. . | April, 
of the pollen, when it disappears, having aided in the development of 
the pollen, no traces of it remaining except a granular matter on 
the superficies of the second membrane, or endothecium of Purkinje. 
Amongst other characteristics, this third membrane is distinguished 
by its colour, which is invariably the same as that of the pollen, 
which it nourishes and brings to maturity. 
M. Chatin’s third paper is “On the Localization of the Fibre- 
cells in some Anthers, and their Absence in others.” The following 
is a résumé of the facts connected with this subject. The fibre-cells 
exist only upon given points of the anther valves, and are localized 
in connection with the following types :—a. The fibre-cells are dis- 
osed along the line of dehiscence (Zhinanthus). 6. They are 
situated in the anthers longitudinally, or towards the line of detach- 
ment of the valves or connective (Chlora). c. They exist only 
at the extremities of the cells close to the pores of dehiscence 
(Solanum). d. They are borne only by one of two valves (Wether- 
ingia rubra). e. ‘They are localized upon the uplifted valves 
(Laurus). f. They extend beyond the valvules (Berberis). g. They 
are scattered and with incomplete threads (Orchis masewla). M. 
Chatin thus sums up the result of his investigations in reference 
to the absence of the fibre-cells from anthers:—a. Anthers dehiscing 
by terminal pores are deprived of fibre-cells, 6. Fibre-cells are 
defective in a certain number of anthers, having longitudinal dehis- 
cence. c. In plants whose stamens are suddenly arrested in their 
development, whether morphologic or histologic, the absence of the 
fibre-cells coincides with the incomplete evolution of the poilen. 
In his paper “On the Placentoid, a New Organ in Anthers,” 
read before the Academy on the 29th of January, M. Chatin says 
that the function of this organ——which is so called from its analogy 
with the placenta of the ovule in the ovarian cell—is to nourish the 
pollen. It appears at the same epoch as the pollen, follows it in 
its development, and disappears when the pollen is mature. The 
Placentoid is absent from the Monocotyledons.; it is wanting in the 
Monochlamydeze and Thalamiflora, and M. Chatim would also add 
Calyciflora, if he had not observed it in Casstca Marilandiea. 
He thinks that the presence of the Placentoid in the Corolliflora 
settles the long-controverted question as to the precedence of the 
Dicotyledonous classes and proves that Gamopetalous exogenous 
plants are more highly organized than Dialypetalous exogens, and 
that among these, the families with the ovary united to the calyx 
should rank above those with the ovary free, that is to say, above 
the corolliflora, 
All botanists have noticed that a deposit of carbonate of lime 
forms on the leaves of Chara, Hippuris, and other submerged 
aquatics. MM. Cloez and Gratiolet supposed that this deposit was 
formed at the moment when the leaf absorbed from the water the 
