
458 THE AMERICAN NATURALIST. [VoL. XXXVI. 
archzeocytes, and that we had here to do with a case of asexual 
reproduction. But, free-swimming larvze, essentially similar to 
those developed from ova in other sponges, being at issue, the 
question whether true ova are not somehow complicated in the 
cell mass whence the larva arises seems to claim to be brought 
on the tapis, all the more, since our knowledge of the hexac- 
tinellidan ovum is far from being satisfactory.” And again, 
p. 188, after mentioning my observations and conclusion, “I 
conceive the mode of origin and growth of the archexocyte 
congeries in the Hexactinellida to be just the same, and it 
seems to me not impossible that in the hexactinellid larve 
which I have seen we have simply a new case of the ‘gem- 
mule larva’ or bud embryo." After referring to Maas's view 
that my conclusion rests upon a mistaken interpretation of a 
process of oógenesis, Ijima goes on to say with regard to his 
own observations, p. 189: ‘So far as concerns the archzocyte 
congeries of the Hexactinellida, I can confidently state that 
among the constituent cells in any stage of its growth, there 
exists not one which, on account of its size or of other external 
peculiarities, can be recognized as an egg. If it be that so 
many cells are aggregated for the sake of the nutrition of a 
developing ovum, this ovum is to be expected to deviate more 
or less morphologically from the rest as it approaches maturity ; 
however, no sign of such a differentiation is noticeable. Further, 
all the cells in a congeries, large or small, are tolerably uniformly 
and compactly packed together, so as to directly touch one 
another; and where they are somewhat loosely arranged, there 
is not a trace of any substance between them. So that I am 
decidedly. against the assumption that some of them are, at 
any stage of the growth of the congeries, engulfed among 
certain others as pabulum. If, after all that, a portion or all 
of the cells in a congeries giving rise to an embryo are still to 
be looked at in the light of blastomeres that have arisen by 
segmentation from a single egg cell, one is driven to the 
assumption that the original ovum is, like the blastomeres 
themselves, as small-bodied as, and indistinguishable from, an 
archzeocyte. This would be very remarkable in an ovum; and 
. moreover, under that supposition, it becomes imperative to deny 
