1048 The American Naturalist. [December 
space of considerable size, but I could not make out that the strand 
itself contained a lumen. 
Neither at this nor at any later time did the digestion tube extend 
into the body behind the bud excepting as a mere diverticulum, though 
there seemed to be a body cavity in this region—more distinctly seen, 
however, at later stages. 
A ciliated band was not present at this time, either at the posterior 
end of the body or at the tip of the bud, though in each place a circle 
of pigment spots was to be seen. 
On the morning of August 11, forty-eight hours after the first sketch, 
shown in Figure 1, was made, the one shown in Figure 2 was drawn. 
Both body and bud had increased in length considerably, but the 
former more, proportionally, than the latter. The digestive tube could 
now be distinctly seen to extend for a considerable distance into the 
bud, though it was constantly being thrust in for a greater or less dis- 
tance and again withdrawn. There was a sort of fold just at the 
entrance that was continually changing its shape and position, by 
reason of which it was impossible to determine exactly what was the 
relation of the intestinal wall to the body wall. 
The strand of tissue in the bud mentioned as being present in the 
preceding stage, has practically the same appearance and relations 
now, excepting that it was proportionally shorter. 
e body cavity behind the bud was now quite distinct, and there 
was a circle of cilia around the body near its posterior end, but none 
on the bud. At this time the bud could be seen to contract somewhat. 
While this sketch was being made the cilia of both the head and 
the posterior end of the body, together with some of the pigment spots 
of the head band were suddenly thrown off, and the animal sank to 
the bottom of the dish and became quiet, whereas it had before this 
time been swimming rapidly about. 
Twenty-four hours later the sketch was made which is represented 
in Figure 3. The head was now much reduced in size, and the body 
correspondingly increased in length. The bud had also increased in 
length somewhat, but much less proportionally than the body. 
The most interesting new feature observed at this time was that 
there was a communication between the digestive tube and the outside 
world through the bud, the anal opening being situated at the tip of 
the latter. Conclusive proof of this was furnished by the fact that a 
mass of fecal matter was seen to pass from the intestine into the bud 
and then out into the surrounding water. But still I could not be 
sure as to the real relation of the digestive tube to the external layer 
