BIOLOGY. 
Prot. 35 
Foraminiferan shell (which is shewn), as an argument for the fluid nature 
of the protoplasm and at the same time as contributing to the “ develop¬ 
mental-mechanics ” of the shell. This constancy leads Rhumbler (315) 
to the conclusion that “the entire form-modification of Foraminiferan 
shells is due to a direct or indirect (sandy shells) separation-product of a 
fluid which is not internally homogeneous, but rather heterogeneous and 
with heterogeneous strains or tensions acting on the surface. This 
heterogeneity is different for different forms, but the same, or at least very 
similar, for the individuals of any species.” Another postulate of Rhum- 
bler’s (315) which experiment proved to be true and thus confirmed his 
conclusion (see above) was “If the protoplasm is of a fluid nature, it must 
extend or spread itself out, on touching the upper surface of the water.” 
This he shewed to be the case in Amoeba limicola. 
The so-called Acanthin skeleton of Acanthometridce , said to consist of a 
calcium-aluminium silicate, not destroyed by strong heating. Contractile 
elements or “myonemes” in Acanthophracta^ as well as in Acanthometra, 
Schewiakoff (338).—Occurrence of silicious needles in Thalassophysa , 
Thalassopiia, and Pachysphcera , n. g., Brandt (41). 
The membrane surrounding Sarcocystis tenella is two layers thick, the 
outer one consisting of two substances, a fundamental, achromatic, flexible 
ground-work which may disintegrate, leaving the other, a stainable sub¬ 
stance in the form of irregular prisms, to simulate a covering of cilia thus 
giving the characteristic striated appearance, Vuillemin (407). 
Presence of a net-like envelope or sheath with hexagonal pores in 
Synura uvella. At the nodes of the reticulum are minute thorn-like 
processes, anteriorly directed, Averintzev (9). 
The enclosing skeleton in the SilicoflagellRta is either of hollow silicious 
rods (Siphonotestales) or of solid ones (Stereotestales), Lemmermann (222). 
Minute structure of the “ coccoliths ” composing the shell in the 
Coccolithophoridse. There are two principal varieties ( a ) unperforated 
forms, and ( b ) coccoliths with the “basal plate” always perforated. Here 
[as in the Silicoflagellata], this peculiarity of the hollow or solid nature of 
the skeletal constituents forms the primary basis of classification, Lohmann 
(231). [See n. E.] 
General structure of Coccoliths and Rhabdoliths, Voeltzkow (401). 
(b) Nucleus, cytoplasm, etc.:—Harper does not agree with Rosell that 
there are two different kind of nuclei in Fuligo varians , the so-called dif¬ 
ferences only being due to fixation, Pammel (280).— Dictydium character¬ 
ized by its bluish colouring matter, and its “dictydin” granules, chemically 
extremely resistant, which are held to be byeproducts of metabolism— 
perhaps analogous to the retractile bodies in Pelomyxa ; very minute 
nuclei, Jahn (166). 
Comparative account of the nucleus in the Lobosa, Penard (289). 
Comparison of the nuclei of Amcebse and other unicellular animals, 
with those of Metazoan and plant cells. FeinBerg (108) is unable to 
distinguish any nuclear reticulum in the nuclei of unicellular animals, by 
the use of Romanowsky's stain, and infers that in these the chromatin is 
all contained in the “ nucleolus.” 
Chromatic grains in protoplasm of Actinosphcerium eichhorni , termed 
chromidia. In monotlialamous Rhizopods, there is a diffuse layer con¬ 
taining nuclear substances, the “chromidial network” ( Arcella , Bifflugia , 
Euglypha), which at certain times (during division) alone represents the 
nucleus. Moreover, in many Protozoa (Ciliata) the protoplasmic network 
may be said to consist of achromatic material, with which chromatin is 
intimatelv united. From a consideration of the nuclear changes and 
divisions in Actinosphcerium , the following idea of the relation between 
chromatin and nucleolar substance is obtained; chromatin, arising from 
the protoplasm, is condensed and therewith organized, in the nucleolar- 
