210 THE ORIGIN OF VERTEBRATES 
This, in my opinion, is the last remnant of one of the old liver-ducts 
which extended from the original stomach and intestine into the 
cephalic liver-mass. This glandular-looking material is shown 
surrounding the pineal eye and its nerve, in Fig. 31, also in 
Fig. 22, and separately in Fig. 92. It is composed of large cells, 
with a badly staining nucleus, closely packed together with lines 
of pigment here and there between the cells; this pigment is 
especially congregated at the spot where the so-called liver-duct 
loses itself in this tissue. The protoplasm in these large cells does 
not stain well, and with osmic acid gives no sign of fat, so that 
Ahblborn’s description of this tissue as a 
peculiar arachnoideal fat-tissue is not 
true; peculiar it certainly is, but fatty 
it is not. 
This tissue has been largely de- 
scribed as a peculiar kind of connective 
tissue, which is there as packing mate- 
rial, for the purpose of steadying a brain 
too small for its case. On the face of 
Fig. 99.—Dnawine or rae ‘+ Such an explanation is unscientific; 
Tissuz WHICH suRROunps certainly for all those who really believe 
THE Brain or AmMOca@TES. in evolution, it is out of the question 
to suppose that a brain-case has been 
laid down in the first instance too large for the brain, in order 
to provide room for a subsequent increase of brain; just as it is 
out of the question to suppose that the nervous system was laid 
down originally as an epithelial tube in order to provide for the 
further development of the nervous system by the conversion of 
more and more of that tube into nervous matter. Yet this latter 
proposition has been seriously put forward by professed believers in 
evolution and in natural selection. 
This tissue bears no resemblance whatever to any form of con- 
nective tissue, either fatty or otherwise. By every test this tissue 
tells as plainly as possible that it is a vestige of some former 
organ, presumably glandular, which existed in that position ; that 
it is not there as packing material because the brain happened 
to be too small for its case, but that, on the contrary, the brain 
is too small for its case, because the case, when it was formed, 
included this organ as well as the brain; in other words, this tissue 
