1894, Zoology. 431 
ZOOLOGY. 
Reproduction of the Foraminifera.—Fritz Schaudinn has 
studied this little known subject and presents’ these results: The repro- 
duction is effected by the division of the protoplasm into, in different 
individuals, a varying number of pieces which secrete shells and grow 
into the adult after different methods according to the species. The 
following modifications of the process are noted : 
I. The division of the protoplasm, the assumption of form, and the 
secretion of the shell by the pieces is completed within the shell of the 
mother. The embryos then leave the mother either, through the mouth, 
or, when that is too small, by a breaking through the shell. II. The 
division occurs inside the mother shell and the embryos escape as - 
naked plasmodia, to develop the shell outside. III. The protoplasm 
leaves the mother shell as a connected mass and all processes occur 
outside the old shell. In all cases the mother, before reproduction, is 
polynucleate, the embryos are usually uninucleate but in some cases 2 
or 3 and rarely more nuclei are present. . 
Schaudinn further calls attention to a peculiar type of nuclear mul- 
tiplication which he finds common in this group but which has hitherto 
escaped notice. He has never seen division into two daughter nuclei, 
but in all forms studied, after a series of changes the mother nucleus 
divides into many daughter nuclei. Briefly summarized these changes 
are as follows: Through the absorption of fluid the homogeneous 
mother nucleus becomes vesicular and then inside this, by means of 
an achromatic filament apparatus, an equal division of the whole 
nuclear substance (chromatin and achromatin) into numerous portions 
follows, and these by disappearance of the nuclear membrane pass 
freely into the cytoplasm and become independent nuclei. 
Regeneration in Hydroids.—Dr. C. B. Davenport attacks’ one 
aspect of the problem of regeneration. One of the fundamental 
assumptions of theories of heredity is that regeneration, like dev elop- 
ment from the egg depends upon the pre-existence of embryonic ares 
but a disputed point is whether embryonic tissue is qualitatively ` j 
t in different parts of the body, i. e., whether it ean produce = 
Certain definite and distinct things or whether it is potentially the same 
Ma. Chblt. XIV, 163, 1894. 
Anat. Anzeiger 1X, 283, 1884. 
