16 On Haeckel’s Group of the “ Physemaria.” 
by Prof. Huxley*; while the inconstancy of its occurrence 
among even the higher Protozoa at once demonstrates the arti- 
ficial character of the group of the Monera, founded by Haeckel 
for the reception of those forms in which a nucleus has not yet 
been recognized. If, as is here intimated, the collar-bearing 
monads of the sponge-colony have only been examined by 
Prof. Haeckel in a dead and preserved state, with all the 
exquisitely beautiful phenomena of life suspended, it is not to 
be wondered at that he has passed them by as the mere indivi- 
dual cell elements of an epithelium-like tissue. But should 
he make himself acquainted with the same when alive, and 
note, as has been done by the writer, the circulating sarcode 
stream of the expanded “collar,” the food intercepted by it, and, | 
after traversing the outer and inner surface, engulfed within 
the substance of the sarcode at its base, then collected into 
pellets and regurgitated through the substance of the body in 
a manner identical with the food-circulation of the higher 
infusorial types, such as Vortecella—witnessing at the same 
time the constant pulsating action of the contractile vesicles 
and all the phenomena attending the several reproductive pro- 
cesses—he will scarcely disallow any longer their title to 
individual and independent recognition. 
Respecting the position, in reference to the ordinary sponge- 
forms, that the single-chambered non-spiculiferous Physe- 
maria occupy, it is very evident that they so far differ 
from such ordinary types that they cannot be correctly styled, 
with their single oscular aperture and no trace of pores, re- 
presentatives of the “‘ PortFERA.” The discovery of these 
new and interesting forms makes it necessary, indeed, to 
effect a slight modification of the usual classificatory system. 
Rejecting the old title of the Porifera, the group may be more 
conveniently divided now into two primary sections—one 
known as the “ PoLyTREMATA,” to include all the ordinary 
poriferous sponges, and a second, to be distinguished as the 
“* MONOTREMATA ’’}, for the reception of all those simple and 
single-apertured types of which the genera Halyphysema and, 
Gastrophysema constitute the characteristic representatives. 
A little later, not improbably, a third section, equivalent in 
value to these two, may have to be instituted, under the title of 
the “ ATREMATA.” 'This type would have no internal cavity, 
and consequently no aperture or pores, the collar-bearing 
monads, with their bodies immersed in a syncytial basis, 
opening directly on the water. Such a type seemed to have 
* Prof. Huxley “On the Classification of the Animal Kingdom,” 
Journal of the Linnean Society, vol. xii. p. 205, 1875. 
+ {Already used for an order of Mammalia.—Ebs. ] 
