158 PROGRESS OF MICROSCOPICAL SCIENCE. 
is like the Bothriocephalus of man—perhaps a species of the same 
genus. This is not supposed to have a cystic state, but to be deve- 
loped from a ciliated embryo taken into the system on raw or badly- 
cooked vegetables, which have been watered by sewage from cesspools, 
in which the eggs will remain alive for months. In the same way the 
eges of the rabbit's tape-worm probably remain in the animal’s drop- 
pings till set free in rain as ciliated embryos. As the rabbit feeds on 
the vegetation watered by such rain, there is no difficulty in under- 
standing how the embryos would reach his alimentary canal.” 
Some of the ‘ Challenger’s’ Diatoms.—In the ‘Annals of Natural 
History’ for February there is an important paper on “ The Type of 
Foraminiferal Structure,” in which the author, Dr. G. C. Wallich, 
points out, among other important items, the circumstance that certain 
of the so-called diatoms found by the ‘ Challenger’ expedition are 
not diatoms at all. He says:—“In the report of the ‘Challenger’ 
expedition, published in the ‘Proceedings of the Royal Society,’ 
1876, vol. xxiv. pl. 21, there are three figures which are described as 
representing ‘true diatoms, to which the generic name of Pyrocystis 
has been given by the discoverers. I am, indeed, grievously mistaken 
if these structures bear the slightest affinity to diatoms, or are any- 
thing else than true oceanic Noctiluce. It would be just as irrational 
to separate the testaceous from the naked Rhizopods, because the 
former have hard coverings and the latter have none, as to regard 
these new forms as distinct from Noctiluca, because they present a 
delicate siliceous wall. The figures of the elongate form, if accurate 
representations, as they doubtless are, show at a glance that the 
structure is not that of any diatom.” 
Gigantic Thread-cells—In a paper read before the Linnean Society, 
February 15, Mr. H. N. Moseley described the thread-cells of some 
Actinozoa found by the ‘ Challenger’ expedition, which, he said, were 
the longest existing forms, being as long as 5 or 6 millimeters, if we 
remember rightly. 
The Tyndall and Bastian Controversy.—Dr. Tyndall recently, de- 
livered a Friday evening lecture before the Royal Institution, in 
which we think, contrary to the views held by the ‘ Lancet, February 
17, that he once more proved his case. Dr. Tyndall had been un- 
lucky in many of his last year’s experiments, and this he clearly 
showed to be due to the atmosphere of the Institution being laden 
with germs from a quantity of hay which was virtually “teeming” 
with them. He then went to Kew, where there is now one of the 
finest laboratories in the kingdom, and there all his experiments were 
perfectly successful. In every case but one the specimens showed no 
trace of life. In that one the experiment broke down and life was 
very freely developed. But why was this? simply because there was 
a small aperture like a pin-hole in the side of the test-tube. A 
perusal of Dr. Roberts’s and Dr. Tyndall’s paper, in the last number of 
the ‘ Proceedings of the Royal Society’ (No. 176), will show the reader 
that the ‘ Lancet’s’ view of the matter is hardly a justifiable one. 
