752 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
peristome ; we may, therefore, conclude that the nucleus has a direct 
action on the movements of the protoplasm. The regeneration of the 
oral apparatus in Stentor has probably the object of repairing the waste 
caused by a prolonged exercise of its functions, while in other Ciliata 
the regeneration appears to be connected with the process of conju- 
gation. 
Two new Infusoria.* — M. A. Certes describes two new Infusoria 
from the neighbourhood of Paris, which he calls Conchophtyrius Metch- 
nikoffl and Odontochlamys Gouraudi. The former is 90-140 p long 
and 60-100 p wide ; the latter was much smaller, being only 20-40 p 
long and 18-35 p wide ; it is allied to Chilodon and Clilamydodon , but it 
is necessary to make a new genus to receive it. 
Rhizopoda of the Lake of Geneva.j — In a short paper on this 
subject, Dr. E. Penard describes a few new species. Hyalosplienia 
punctata differs in having the membrane not smooth, but distinctly 
covered with very small round scales, and in its smaller size, from any 
member of the genus yet described. Quadrula globulosa is the first of its 
genus in which the test is almost spherical instead of being elongated 
and flattened. Campascus triqueter , which is abundant near Geneva, is 
very closely allied to C. cornutus , but is distinguished by having no 
horns. Acanthocystis Lemani is a fine species, the ectosarc of which is 
almost always filled with yellowish-green granules, which were first 
thought to be parasitic Algse ; it was, however, recognized that they 
were small Dinobrya which had been captured by this Heliozoon. The 
spicules exhibit remarkable variations, some being much larger than 
the rest, and expanding suddenly at one end; others enlarge more 
gradually. All, whether typical or not, are constructed on the type of 
a funnel. The spicules are further remarkable for being two or three 
times as long as the diameter of the body. 
Origin and Growth of the Shell in Freshwater Rhizopods.J — 
Dr. L. Rhumbler does not agree with Verworn’s conclusion that the 
shells of freshwater Ehizopods do not grow or change after they have 
been once formed, that is, after the division has been effected. There 
are three ways in which the cases of these Rhizopods arise : — (1) By 
the constriction of the parent shell, as in Lieberkulinia , Diplophrys , and 
Lecythium ; (2) by the formation of a new and independent shell, as in 
Microgromia ; (3) from materials which the parent Protozoon furnishes, 
as in Euglypha and Difflugia. But it may be frequently observed that 
the new shells contain fragments which, on account of their size, could 
not have been included in the parent animal. The question thus arises : 
In what sense are these large fragments secondary accretions? In 
answering this, Dr. Rhumbler describes the formation of the case in 
Difflugia acuminata during division ; the occurrence of regeneration in 
Difflugia spiralis; the growth of shells with protoplasmic cementing 
substance, as in several species of Difflugia; the gradual growth of 
Arcella-shclls and the growth of the chitinoid case of Centropyxis 
aculeata. The division of Difflugia acuminata shows that firm portions 
* Mem. Soc. ZooL Fiance, iv. (1891) 6 pp. (1 pi.). 
f Arch. Sci. Phys. et Nat., xxvi. (1891) pp. 134-56 (1 pi.). 
X Zeitschr. f. Wiss. Zool., lii. (1891) pp. 515-50 (1 pi. and 2 figs.). 
