478 
SEITARO GOTO 
second form of gasterozooids is also found anywhere on the colony 
without any regular arrangement, but generally they are far less 
numerous than the first form. They are thick and comparatively 
short, the hypostome is large and prominent, the mouth is widely 
open, and the tentacles are arranged strictly in a single whorl 
and usually less contracted than in the first form (fig. 8). At 
a glance these appear to be essentially different from the first 
form and were so regarded by Inaba, the different arrangement of 
the tentacles being especially noticeable; but close observations 
have shown that they are connected by all degrees of intermediate 
stages with the first form. In fact the polyps of the second form 
are those that have gorged themselves with prey. It is true that 
in none of my sections of these polyps have I been able to recog- 
nize the nature of the prey, but the gastric cavity was filled with 
a half digested material. It is rather hard to understand how 
the different arrangements of the tentacles pass so smoothly into 
each other, but when we take into account the great elasticity 
of the body wall such a feat is not impossible. The third group of 
gasterozooids includes young ones without a mouth and with a 
single whorl of tentacles. These are especially numerous near the 
mouth of the chitinous shell (fig. 6). 
The dactylozooids are long and slender, and, when numerous, 
form a thick zone along the mouth of the hydroid shell (fig. 5) ; 
their number appears to vary a great deal in the different colonies, 
only a few being found here and there in some. They are usually 
situated close to the margin of the chitinous shell but are some- 
times found also on the inner surface at a short distance from the 
mouth. The individual polyps are subject to some variation. 
Stechow^Mescribes them as having a mouth, and with nearly the 
whole hypostome bearing short tentacles. I find that the form 
and number of these tentacles are subject to great variation. 
Thus, in the portion of a colony reproduced in fig. 6, most of the 
spiral zooids are seen to be provided with only a single row of ten- 
tacles which are so exceedingly short as to appear like so many 
simple knobs, but one of them has many tentacles which are 
" hoc. cit. : '09, p. 22. 
