NOTES ON RETICULARIAN RHIZOPODA, 41 
mere undifferentiated protoplasm, Gromea might properly 
be regarded as pertaining to a higher type of organisation ; 
but recent researches, notably those of Professor R. Hertwi ig 
and Professor F. E. Schulze, have shown that certain types 
of Foraminifera possess nuclei indistinguishable from analo- 
gous bodies in the chitinous fresh-water Rhizopods. Pro- 
fessor Leidy, in his elaborate work upon the ‘ Fresh-water 
Rhizopods of North America, just published, practically 
confirms this view by treating Gromia as a genus of 
Foraminifera. 
B. Test imperforate; normally porcellanous, sometimes 
encrusted with sand; under starved conditions (e.g. in brackish 
water) becoming chitinous or chitino-arenaceous ; at abyssal 
depths occasionally consisting of a thin homogeneous, umper- 
Sorate, silicious film. 
II. MitioLt1pm.—Concerning the genus Sguamulina there 
seems still considerable doubt. Judging from Max Schultze’s 
description and figures it seems to be a monothalamous, ad- 
herent, porcellanous species, not far removed from the simpler 
varieties of Nubecularia. 
Of the Dactyloporine there is little to be said at the 
present time inasmuch as they may have to be removed, 
either entirely or in part, to the calcareous Alge ; but as 
yet we have no authority for so important a step beyond 
the brief preliminary notice of M. Munier-Chalmas’s re- 
searches, and it will be generally admitted that there are 
two sides to the question. 
C. Test invariably arenaceous. 
III. AstrorHizip%.—Coarse sandy forms, usually of 
large size, and monothalamous ; often branched or radiate, 
but never truly septate (7. e. as distinct from mere constric- 
tion). Polythalamous forms never symmetrical. 
It is probably that this family may eventually require 
subdivision ; as now proposed it includes all the deep-water 
arenaceous recent Rhizopods except those of the family 
Lituolide. 
IV. Lirvotipa.— Comprises sandy isomorphs of the 
simpler hyaline types’ (Lagena, Nodosaria, G'lobigerina, 
Rotaha, Nonionina, &c.), together with some adherent 
species. Septation of the polythalamous forms imperfect ; 
chambers sometimes subdivided or labyrinthic. 
V. Parker1pa#.—Large, spherical, lenticular, or fusiform 
fossils ; constructed either on a spiral plan or in concen- 
