320 
POPULAR SCIENCE REVIEW. 
The Zanzibar Copal and the Copal-tree . — A very interesting paper was 
that recently read before the Linnean Society (April 20) on this subject. It 
was a letter from Dr. Kirk, of Zanzibar, which was read by Dr. Hooker. It 
referred to the identification of the modem copal-tree, Traehylobium Home - 
mannianum, with that which yielded the Zanzibar Copal or Gum Animi, 
now found in the earth on the East Coast of Africa, and often where no copal 
yielding tree now exists. Little doubt now rests as to the identity of the 
semi-fos3il with the living tree, inasmuch as bijugate leaf, flower-bud, 
flower, ovary and stamens, characteristic of the latter, have been discovered 
in the so-called Animi. Dr. Kirk is inclined to account for their difference 
in quality by a molecular or chemical change in the buried material ; im- 
proving it thereby, and as a consequence increasing its market value. 
Floral AEstivations. — At the meeting of the Linnean Society (June 1, 
1876), the Rev. G. Henslow read a paper on “Floral .Estivations,” in 
which he explained the origin of eight kinds, more particularly referring to 
the new term “ half-imbricate.” This latter he applied to a large number 
of cases ranging from perfectly regular to extremely irregular and zygo- 
morphic flowers of the pea and snapdragon. The author added a note on a 
new theory of the cruciferous flower, based on a quinary type. He also dis- 
puted the tenability of Chorisis in the pairs of long stamens, regarding their 
occasional union as indicative of evolutionary advance and not retrogres- 
sion; as cohesion is a subsequent stage to freedom, except in the rare cases 
of atavism indicated by solution and dialysis. The justness of Pfeffer’s 
view of the corolla of Primula being an outgrowth of the andrcecium he 
calls in question, giving several reasons in support of this adverse opinion. 
African Coffee-plants . — A paper was read before the Linnean Society 
(April 20), on the African species of the genus Coffea , Linn., by Mr. W. P. 
Hiern. As now restricted this genus belongs to the Old World, attributed 
American species being referred to other genera. Out of seven Indian spe- 
cies one formerly was cultivated, but has been superseded by African plants. 
The author distinguishes thirteen species as indigenous to the African con- 
tinent, and two to Mauritius and Bourbon. Of the former, two kinds are 
found in East and Central Africa, the remainder ranging along the West 
Coast. The ordinary commercial coffee, he shows, grows wild in Abyssinia 
and other parts of Africa ; and as to the celebrated Mocha coffee, he regards 
it as but a doubtful variety of the ordinary sort. A technical description is 
for the first time given of Liberian coffee, C. . liberica. This only recently 
has acquired importance, having been introduced into England in 1874 by 
Mr. W. Bull, the horticulturist. Already, however, its fame is spreading 
far and wide among coffee-planters, especially those of Ceylon. Its intro- 
duction there ha9 been regarded as a great boon, and justly so; its quali- 
ties far surpassing any kind hitherto known. This undoubted distinct 
species of coffee is robust, hardy, and very productive. It is large-leaved 
and big-berried, and the latter in flavour and aroma are very superior to the 
common C. arabica. As it thrives at lower altitudes and in districts inimical 
to the latter, its commercial importance hereafter is likely to be very great. 
Other useful qualities attributed to it time and experience may test. 
Peculiar Food of Ants. — Mr. Francis Darwin read a paper “ On the 
Glandular Bodies on Acacia sphcerocephala and Cecropia peltata , serving as 
