JUNE 138, 1884.] 
Ray, ‘ Natura non facit saltum,’ needed modification. 
He had noticed that such departures usually occur 
in different parts of the country at the same time. 
The common calla lily, for instance, had, in several 
cases during the present season, developed a spathe 
some four inches below the perfect flower: in other 
words, the usually naked flower-scape of the Richardia 
had borne a bract. Flowers with a pair of more or 
less imperfect spathes were not uncommon in'some 
seasons; the peculiarity of the cases now referred to 
being the interval of several inches on the stem, which 
justifies the application of the term ‘bract’ to the 
lower spathe. Numbers of such specimens had been 
brought to him from the neighborhood of Philadelphia, 
while others had been sent from Ohio, Indiana, and 
Illinois, hundreds of miles apart. In view of such 
circumstances, he believed that varieties might spring 
from widely separated centres by the operation of a 
general law entirely independent of environment. We 
know that distinct forms do spring through single in- 
dividuals from seed, and that, after struggling success- 
fully with all the vicissitudes of its surroundings, the 
new form may succeed in spreading, through the lapse 
of years or ages, over aconsiderable district of country. 
But the idea, that always and in all cases species have 
originated in this manner, presents occasionally diffi- 
culties which seem insurmountable. In the case of 
the similarity between the flora of Japan and that 
of the eastern portion of the United States, we have to 
assume the existence of a much closer connection be- 
tween the land over what is now the Pacific Ocean, 
in comparatively modern times, in order to get a satis- 
factory idea of the departure of the species from one 
central spot, and to demand a great number of years 
for some plants to travel from one central birthplace 
before the land subsided; carrying back species in 
geological time farther, perhaps, than geological facts 
would allow. But if we can see our way to a belief 
that plants may change in a wide district simultane- 
ously in one direction, and that these changes, once 
introduced, may be able to perpetuate themselves till 
a new birth-time should arrive, we have made a great 
advance towards simplifying the problem. —— Mr. Ed- 
ward Potts stated that a correspondent in Jamaica had 
failed to find there a single species of fresh-water 
sponge. It had been suggested that these organisms 
affect higher latitudes and elevated regions, — an 
opinion which the speaker was disposed to hold. In 
all the water-pipes examined by him, from the imme- 
diate vicinity of the basin, he had found abundant 
sponge-growth; and it had been asked if such growth 
might not be a cause of obstruction. In some sec- 
tions of filled-up pipes, taken at a greater distance 
from the supply, he had found no sponge; the block- 
ing substance being clay with iron impregnation. 
He had found, that, where masses of Mayenia Leidyi 
were strongly mixed in these pipes with iron, the 
skeleton spicules had undergone a curious change. 
In nearly all spicules, especially when young, a fine 
line can be traced down the middle; but, in the spe- 
cimens referred to, a clear channel occupying two- 
thirds of the entire space, with openings at the ends, 
could be observed. It was suggested that the change 
SCIENCE. 
137 
was due to the iron retarding the deposit of siliceous 
matter in the central channel of the spicules. In the 
birotulate spicules of the same masses the margins of 
the disk-like ends were eliminated, leaving them in 
the form of rays. 
Davenport academy of natural sciences, Iowa, 
May 30. — Mr. W. H. Pratt called attention to some 
interesting peculiarities in several of the flathead 
skulls from the Arkansas mounds, in one of which 
appears a large ‘ Inca bone,’ formed by the presence 
of a horizontal occipital suture in addition to those 
usually present; and in another the ear-openings are 
nearly closed by the bones growing into them. He 
also exhibited a number of ossicles — minute bones 
of the internal structure of the ear — which had been 
extracted in cleaning out the earth which filled the 
cavities. —— The honey-dew, which has been observed 
in such remarkable profusion this season, and the va- 
rious opinions regarding its origin, came up for discus- 
sion; and twigs from several trees were presented 
for examination. The observations of several mem- 
bers seemed strongly to support the theory that the 
substance is, partly at least, produced by the bark- 
louse, Pulvinaria innumerabilis, and perhaps kin-. 
dred species. This opinion was sustained by the fol- 
lowing facts: 1°. It is found that the honey-dew is 
not deposited on the leaves at the top of the trees, 
hence is not an exudation from the leaf. 2°. It is 
not found on the white maples which are not infested 
by the bark-louse, several instances of which have 
been noticed. 3°. It is observed to a less extent on 
the box-elder tree; and on examination it is found 
that that tree is also infested by the Pulvinaria, 
though not so badly as the maple. 4°. It is observed 
that the honey-bee, which collects the honey-dew 
with great avidity, very often, and especially when 
the substance is considerably dried and hardened 
upon the leaves, proceeds directly to the under side 
of the limb, where the insects are fixed, and, running 
along the branch, examines them carefully, appar- 
ently seeking its supply from that source. 5°. It is 
also observed that there is always more or less of it 
upon the insects, especially in the morning; and, upon 
close examination, all are found to contain a quan- 
tity of the same substance. In view of these facts, 
the opinion was expressed, that, although further and 
thorough investigation is necessary to establish the 
fact, this will be the final solution, —that the honey- 
dew is largely the product of the Pulvinaria, the sap 
being by it extracted from the tree, and elaborated by 
the insect organism into this sweet substance, as is a 
similar or perhaps identical substance by some of 
the Aphides, and honey by the honey-bee. 
Natural history society, Cornell university, Ithaca, N.Y. 
May 29.—Mr. C. S. Prosser read a paper on sil- 
ver in the Chemung and Catskill, the principal part 
of which was devoted toa consideration of the re- 
cently discovered silver-deposits near Oneonta, Otsego 
county, N.Y. Itis claimed that valuable deposits 
of gold and silver have been found in the Catskily 
