ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
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number of varieties have been seen. Arcella vulgaris is common. 
Euglypha reticulata and various species of Diffiugia are not rare, but 
ciliated and flagellate Infusoria are ; only a few Monads or Euglense 
have been seen. The differences in the comparative abundance of 
Rhizopods and Infusoria are, however, not difficult to explain. 
Protozoa from Cape Horn.* — M. A. Certes describes the Protozoa 
collected by the ‘ Romanche ’ on its expedition to Cape Horn. In his 
general introduction he notes the interesting fact that dry deposit, 
gathered in 1883 and exposed for the first time in 1888, contained germs 
which regained activity when placed in culture solutions. Thus, there 
appeared Oikomonas mutahilis, various monads, a flagellate Infusorian 
very like Phacotus lenticularis, some algae. Bacillus amylohacter, &c. 
Among the Rhizopods were three new species of Nebela, two of Trinemaf 
one of Centropyxis^ two of Cadium, and four new Radiolarians. 
Nucleus of Loxophyllum meleagris.f — Prof. E. G. Balbiani has 
closely studied the nucleus of this ciliate infusorian. He finds that it is 
formed of a varying number of joints or segments, of which there may 
be twenty or more, which are connected with one another by the 
enveloping membrane, but have their contents perfectly distinct. 
These contents consist of one or more nuclear cords which form more or 
less numerous convolutions, and by an intermediate substance which 
contains a large number of granules. Observations show that, 
in certain cases at any rate, the nucleus does, in a state of repose, 
contain a chromatic filament, or several, which are free and distinct. 
The nuclear cords present a very fine transverse striation analogous to 
that which is seen in the nuclei of the cells of the larva of Chironomus ; 
this striation is probably due to the alternation of discs of chromatin 
with layers of achromatic substance. The addition of a weak solution 
of ammonia causes the nuclear cords to swell and break up into pieces, 
the axis of which is occupied by a homogeneous chromatic filament, or by 
a row of chromatic granulations, while the periphery is formed by a 
pretty thick layer of homogeneous achromatic substance. Nothing 
comparable to nucleoli was seen in the nucleus, but they are probably 
represented by the granulations in the nuclear fluid. 
' Nuclei of Urostyla.J — Prof. R. S. Bergh describes the nuclei and 
the hitherto unobserved micronuclei of Urostyla grandis and Urostyla 
intermedia n. sp. The former are exceedingly numerous, 200 or so, 
and seem to be united by fine filaments ; the latter number on an 
average ten, and are in TJ. intermedia smaller, in Z7. grandis larger than 
the nuclei. Before division, the breadth of the Infusorians increases 
and the length decreases. As the new contractile vacuole and adoral 
zone are formed, the distinction between nuclei and micronuclei for 
a time disappears ; the micronuclei are afterwards seen to assume the 
coil stage so rarely observed in Infusorians, and also a spindle phase 
before they divide ; the nuclei unite in a single mass, of filamentar 
structure and ribbon-like form, which presently exhibits fragmentation. 
* Rec. Mission Sci. du Cap Horn, vi. (1889) pp, 53 (6 pis. and 9 figs.). 
t Zool. Anzeig., xiii. (18u0) pp. 110-5, 132-6. 
X Arch, de liiol., ix. (1889) pp. 497-514 (1 pi.). 
