638 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
Benda-Heidenhain method. Before describing the conjugation he has 
some notes on the mitosis, pointing out that in this process the pseudo- 
podia are always retracted, which they certainly are not in the figures 
given by previous investigators. There seems to have been confusion 
between forms in act of dividing and forms separating off from plastogamy. 
From 2-30 individuals may unite loosely in plastogamy, but even then 
they conjugate (with nuclear fusion) only in pairs. Before the forma- 
tion of the fused or cleavage nucleus there occurs in each cell a mitotic 
reduction-division, half of each nucleus being got rid of. Dr. Schaudinn 
promises to return to a fuller discussion of this interesting discovery. 
Parasitic Rhizopod in Ascitic Fluid in Man * — Drs. E. von Leyden 
and F. Schaudinn report on the interesting discovery of amoeboid para- 
sites in the abdominal fluid of two patients suffering from ascites. 
The medical aspects of the cases are described by von Leyden ; the 
organism has been particularly studied by Schaudinn, who names it 
Leydenia gemmipara. 
When contracted, the Rhizopod is spherical or irregularly polygonal, 
and usually with superficial protuberances ; the diameter varies from 
3 ijl to 36 /x ; the plasma shows very abundant yellowish refractive gran- 
ules and a hyaline peripheral layer. Both hyaline and granular pseudo- 
podia are formed, and are connected by lamellar plasmic plates as if 
webbed. Their resemblance to those of Placopus is very striking. 
Plasmodial aggregates of as many as forty individuals were observed. 
The movements are relatively sluggish. 
The enclosures in the plasma are in part fatty, in part crystal-like 
and excretory (?), in part remains of food. Numerous vacuoles occur, 
and a slowly pulsating contractile vacuole is also present. The general 
structure of the plasma is alveolar. Schaudinn repeatedly observed the 
engulfing of red and white blood-corpuscles. 
Only one nucleus is present, a simple clear vesicle, almost always 
one-fifth the diameter of the cell. Multiplication may be either by 
fission or budding, and shows direct nuclear division. In some cases 
the reproduction was very rapid, and great variety of size and aggrega- 
tion occurred. 
The authors emphasise the fact that they refrain at present from 
any conclusion as to the connection between the parasite and the dis- 
eased conditions of carcinoma, &c. 
Webbina and Vitriwebbina.f — Mr. F. Chapman has made an in- 
vestigation of these two genera of Rhizopods. Webbina , when first 
made a genus, appears to have been ill defined, and it is necessary to 
follow the definitions of Jones, Parker, and Brady, who in I860 placed 
the genus upon a substantial basis. Those examples of adherent 
Foraminifera which resemble Webbina externally but have a tabulate 
shell-wall, should be retained in the genus Vitriwebbina. The 
typical arenaceous Webbina, so far as Mr. Chapman is acquainted with 
them, have simple non-septate chambers. Vitriwebbina appears to. be 
closely related to Pamulina in having similar septate, i polymorphine, 
commencements. 
* SB. K. Preuss. Akad., 1896, pp. 951-63. 
t Ann. Mag. Nat. Hist., xviii. (1896) pp. 326-33 (4 figs.). 
