539 
The sections of the anterior segments show in a convincing 
manner that a new head had actually been developed. An ecto- 
dermic invagination of considerable size and closely resembling a 
stomodaeum appeared in the sections (see fig. 4 St.) It had not 
grown back far enough to unite with the digestive tract of the 
crafted part, nor 
had the latter grown 
forward to form a 
new pharynx. The 
anterior end of the 
digestive tract had 
closed forming a 
blind diverticulum 
at the base of the re- 
generated segments. 
It was impossible to 
determine to what 
extent new cells had 
formed at the an- 
terior end of this di- 
verticulum, if at all, 
and it, therefore, 
seemed questionable 
whether the dige- 
stive tract would 
have united with the 
ectoderm, even if 
the grafted worm 
had lived longer. 
An enormous di- 
latation of the vas- 
cular system was 
present in the head 
(figs. 4, 5 and 6 
Bv.) This was con- 
nected on either side 
with small lateral 
branches, which pas- 
sed ventrally on both 
sides of the cerebral ganglion, outside the commissures, and joined 
the ventral blood vessel on the dorsal side of the nerve cord. These 
