232 
H 
H 
100 jj 
Fig. 3. Metafolliculina andrewsi showing: a, frayed, 
distal end of neck extension; b , neck extension with- 
out spiral whorls; c, lip of neck; d, spiral whorl; and 
e, neck. 
lip-making is very far removed from the area 
originally active in the making of the first 
tube [neck], . . . [since] the arms are made 
from the region very far from the anterior 
end of the larval swimmer. 
While my single observation proves that a 
neck extension, even though imperfect, can be 
the product of the sessile stage it does not ex- 
clude other extension possibilities. 
II. Neck Extensions by the Stage Remaining in 
the Lorica following Binary Fission. 
As previously stated, the proximal portion 
following binary fission metamorphoses into a 
sessile stage, characterized by peristomal lobes. 
PACIFIC SCIENCE, Vol. XVIII, April 1964 
This stage persists under laboratory conditions 
from one to several days. This metamorphoses 
back into a swimmer but there is every reason 
to assume that, after a period of rest, it might 
undergo binary fission or indeed produce, as 
previously described, an imperfect neck exten- 
sion. However, this is mere conjecture. 
III. Neck Extension by the Stage Leaving the 
Lorica following Binary Fission. 
Although this stage might possibly produce 
a neck extension, it was never observed to make 
one. Swimmers were often observed which 
seemed to experience considerable difficulty in 
leaving the lorica, but finally all were able to 
do so. 
IV. Neck Extensions by a New Swimmer (or 
Swimmers) entering Another Lorica. 
Lagotia viridis (Fig. 4), with well-developed 
sac ( g ) and neck (e ) , was observed trapped in 
its lorica by a swimmer whose attachment point 
( b ) was located either on or just below the well- 
developed lip (c). While at first sight this stage 
of neck extension might seem to fall under III 
( the Stage Leaving the Lorica following Binary 
Fission) such was not the case. As far as is 
known, L. viridis does not make neck extensions. 
Although it undergoes binary fission, the distal 
portion metamorphoses into a swimmer which 
leaves the old lorica to start the process anew. 
Moreover, when first observed the anterior or 
pectinellae end of the swimmer pointed down 
into the neck and only later contracted and 
formed a living plug which completely closed 
the neck (e ) . During this time the entrapped 
folliculinid lay motionless at the proximal end 
of the sac. As in M. andretvsi, a viscous secre- 
tion appeared just above the lip (c). There was 
no apparent movement either of the swimmer 
or of its fused cilia. Whereas the folliculinid in 
the sac was a light bottle green, the swimmer 
attached near the lip was a deep violet. During 
the next 2 hours this became lighter until 
finally it approximated the green of the follicu- 
linid in the sac. Slowly there emerged what at 
first was mistaken for a proboscis. This came not 
from the very top of the old lorica but rather 
more from the side and extended (as illustrated) 
to the top of the old sac. Not once, however, 
