Dr. Wallich^ on the Polycystina. 61 
Of Professor Schultze^s classification of the Rhizopods_, as 
set forth in his treatise ' Uber den Organismus der Poly- 
tlialamien (Foraminiferen)/ Leipzig^ 1854_, it is only requi- 
site to state that I entirely concur with Dr. Carpenter in 
considering any Ordinal division based on the presence or 
absence of a test as altogether untenable ; and that 
throughout the elaborate work in question the occurrence of 
a nucleus in the Foraminifera is wholly negatived. Carpenter 
affirms with perfect truth that no such organ is to be found 
in this family. I am inclined to believe, however_, that, 
whilst the bodies called yellow cellules are only derived 
from the nucleus in the two higher Orders, in the lower they 
normally constitute its representatives. It will presently be 
seen that on the possession or otherwise of the organ, in a 
definite form, I base my Ordinal separation of the Ehizopods. 
There is a very voluminous monograph on the " Radiola- 
rian^^ Order of the Rhizopods,^ allusion to which would gladly 
have been avoided by me, inasmuch as the views regarding spe- 
cific limits therein contained seem calculated rather to retard 
than to advance our knowledge of the organisms of which 
it treats, by attaching weight to those minute and endless 
structural differences which, occurring amongst creatures 
so simple and therefore so pre-eminently susceptible to 
varying external influences, yield characters of no real 
significance. It is obvious, moreover, that in a work based 
on such an estimate of all these minute differences we must 
expect to find the nomenclature of the subject, already suffi- 
ciently perplexing and cumbrous, rendered doubly so by the 
introduction of a host of new names ; whilst the task of 
extracting whatever novel information it contains would in- 
volve a degree of labour few persons have the inclination, 
and still fewer the leisure, to bestow upon it. 
In saying this much, I most earnestly disclaim all intention 
of speaking uncourteously, for no one can be more deeply 
impressed with the almost unparalleled amount of industry 
the author has brought to bear on his undertaking — industry 
misdirected, it is true, but nevertheless most laudable. 
The last, and, as I conceive, by far the most important 
classification of the Rhizopods, is that recently offered by Dr. 
Carpenter, an abstract of which originally appeared in the 
' Natural History Keview ' (Oct., 1861, p. 456), but which has 
been more fully given in " The Introduction to the Study of 
the Formninifera/ published by the Eay Society. Of this work, 
and of another on the same subject by Professor Williamson, 
* 'Die lladiolarien (Rhizopoda Jladiaria'). Von Dr. Ernest Haeckel. 
Berlin, 1863. " ' 
