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PACIFIC SCIENCE, Vol. XVIII, April 1964 
by swimmers locating in empty tests, while I 
maintain it is less improbable to imagine the 
adult can attempt a secondary imperfect neck 
or even a third while dwelling in the old test. 
Following Andrew’s suggestion, glass plates 
to which were attached Metafolliculina an- 
drewsi, M. nordgardi, Parafolliculina violaceae, 
and Lagotia viridis were brought into the lab- 
oratory and the following neck-extension pos- 
sibilities were studied: 
135 (J 
Fig. 1. Metafolliculina andrewsi as viewed from the 
right side showing: a, peristomal lobes; b, extended 
body; c, neck without extensions; d, nucleus; e, sac; 
and f, body attachment point. 
I. Neck Extensions by the Stage that secreted 
the Lorica. 
Although living M. andrewsi and M. nord- 
gardi (Matthews, 1963) with and without ex- 
tensions were present, these were ignored for 
the moment because, even if subsequent neck 
extensions were formed, the possibility re- 
mained that these could be the product of some 
stage other than that which secreted the lorica; 
for example, a new swimmer (or swimmers) 
that had entered an empty lorica. To exclude 
this possibility the aquarium in which these 
plates were held was completely covered with 
black paper except for one small area in which 
unetched glass slides were placed. By this method 
the entire lorica-forming process of M. andrewsi 
was observed. Thus it was made certain that the 
folliculinid occupying a particular lorica was 
indeed its original builder. Metamorphosis of 
these original lorica builders into swimmers 
was frequently observed and, as each swimmer 
vacated its lorica, a small, but easily distinguish- 
able body attachment point (Fig. 5d) was left 
in the proximal region of the empty sac. Like- 
wise, binary fission and the subsequent meta- 
morphoses into sessile and motile stages was 
observed. In such instances the original body 
attachment point appeared unaltered either as 
to size, shape, position, or number. 
In approximately 25 M. andrewsi , only one 
instance of a neck extension was observed. This 
particular folliculinid was brought to my at- 
tention by my inability to bring into sharp 
focus the region just distal to the lip. When 
first observed at 8:25 AM the organism, with 
a single point attachment, lay contracted in the 
proximal end of its sac. Slowly it relaxed and 
extended its peristomal lobes above the cloud- 
like, viscous mass which surrounded the lip, only 
to contract again into the sac. The relaxation of 
the body and the freeing of the peristomal lobes 
above the distal opening of the neck had been 
observed frequently in other specimens of M. 
andrewsi. In such instances, as the body relaxed 
the spirally twisted peristomal lobes were car- 
ried aloft where their pectinellae burst into a 
"running flame” of activity resembling the spiral 
ignition of a gas stove burner. In the present 
specimen such was not the case. As the body 
relaxed (Fig. 2 g) and the peristomal lobes ( a , 
