a2 SVYONGES 
vrowth much more suddenly arrested. Hence the twigs present a more trun- 
cated aypearance. ( See Fig. 17, F, G,and J, and Fig. 16, A andB). In 
some cases the arrested twigs of the interior present’ acup-like depression at 
the extremity. (See Fig. 17, H, and the one directly above it.) In these 
twigs the hollow membrane is sealed, but is covered with only a thin layer 
of horny matter. This is evidently the consequence of the twig having passed 
a little beyond the sarcoteinto the lining membrane of the tube. Or rather 
this is the condition under which such twigs are found, but it is quite probable 
that the lining membrane has absorbed a portion of the sarcode and grown 
around the twigs before the usual quantity of horny matter was deposited on 
their extremities. 
VARIATIONS IN SKELETON GROWTH. 
I have said that new fibers usually anastomose with new growths, and 
this is true where an unbroken internal. membrane occurs; thus this is the 
normal method of growth, but where new and growing fiber comes in contact 
with an old growth, a kind of anastomosis takes place. In this case the grow- 
ing tip of the new twig comes in contact with the horny side of the old growth 
and is soldered there by an accumulatioa of additional horny matter, secreted 
quite likely by both the old and the new sarcoé® — But in all such anastomosis 
there is no connection between the internal hollow membrane of the fiber of one 
growth with that of another. That is, the new growth does not penetrate into 
the horny covering of the old growth as it does into the membrane of the new. 
Another peculiar feature of this method of anastomosis is that when the 
new growth comes in contact with the old, the new twig, no matter at what 
angle it comes against the horny side of the old growth, usually continues to 
