494 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
Protozoa. 
The Principles of Skeletal Architecture in Protozoa.* * * § — Dr. F. 
Dreyer endeavours to give a mechanical rationale of the forms of 
skeleton in Rhizopods. He deals first with the cuticular shells of 
Thalamophora and the central capsules of Radiolaria, secondly with axial 
skeletons of Radiolarians and Heliozoa. Starting from the primitive 
chitinoid shell, in its various forms, he traces the strengthening of this 
by inorganic materials, especially carbonate of lime, or by the accretion 
of extrinsic particles. He follows Neumayr in tracing the parallelism 
between the agglutinate and calcareous Foraminifera. He regards the 
central capsule of Radiolarians as comparable with the cuticular shell of 
Foraminifera. In treating of axially arranged skeletons, Dreyer starts 
from the transitory formation of an axial strand in a pseudopodium. In 
Heliozoa he distinguishes two stages (1) in Actinosphserium , &c., in 
which the axial needles are isolated, (2) in Raphidiophrys , &c., in which 
the needles meet in the centre. Among Acantharia, one stage — an elastic 
movable supporting apparatus — is reached in Acanthometra, another — a 
compacted and rigid framework — in Acanthophracta. Dreyer’s sugges- 
tions deserve to be pondered over; justice can hardly be done to them 
without giving detailed illustrations of his way of interpreting the facts. 
Infusorians in the Stomach of Ruminants-t — Herr A. Schuberg 
has studied some of the Infusorians which he and other investigators 
have found in abundance in the rumen and reticulum of rumiuants. 
They eat solid particles and are rather commensals than parasites. 
Large species of Diplodinium often swallow their companions of the 
genera Isotricha and Dasytricha. Schuberg describes in detail the 
division of Dasytricha ruminantium , which is of especial interest in con- 
nection with the change in the position of the new mouth formed after 
division. After discussing the behaviour of the nuclei, the author pours 
scorn upon those who pretend to give a “mechanical explanation” of the 
division of Infusorians. The structure of the Ophryoscolecidae, which 
is extraordinarily complex, is then discussed, with especial reference to 
the marked distinction between ectoplasm and endoplasm. The pro- 
cesses of division in Ophryoscolecidae are also described. 
Clathrulina and Hedriocystis.J— Mr. W. J. Simmons reports the 
discovery in Calcutta of Clathrulina elegans, first found by Cienkowski 
in St. Petersburg, and afterwards in various parts of central and western 
Europe, and in North America, and of Hedriocystis pellucida of Hertwig. 
W e have here another example of the wide distribution of the Protozoa, 
a subject to which microscopists in India might profitably direct their 
attention. 
Difilugise of Bottom of Lake of Geneva.§ — Prof. _H. Blanc shows 
that the numerous nuclei sometimes seen in a Difflugia do not arise 
spontaneously in the protoplasm ; they are the products of successive 
divisions. These nuclei, surrounded with protoplasm and some grains 
* Jenaische Zeitschr. f. Naturwiss., xxvi. (1891) pp. 204-96 (5 pis.), 
t SB. Physik.-med. Gesell. Wurzburg, 1891, pp. 122-37. 
1 Science Gossip, 1892, pp. 124-7 (9 figs.). 
§ Arch. Sci. Phys. et Nat., xxvii. (1892) p. 472. 
