696 JULIAN 8. HUXLEY 
Fig. 10 (x 64).—Zooid reaching stage 5. The stolon was attached to 
another zooid, and showed active circulation. It was hard to be sure 
whether the heart was beating. 
Fig. 11 (x 100).—Zooid in stage 5. Stolon as in 10. Zooid ectoderm 
cuboidal. Solid organ-remains fill most of the zooid. 
Fig. 12 (x 64).—a. Zooid in stage 4, after two days. 6. The same, 
nine and a half hours later (from a different aspect). Stolon as in 10. 
Fig. 13 (x 64).—Zooid in stage 5 of reduction. Zooid of the same 
opacity as the stolon. 
Fig. 14 ( x 64).—Zooid in stage 5-6. Opacity as in 13. 
Fig. 15 (x 64).—Zooid in stage 6. Some remains of organs visible. 
Figs. 16-18.—Reduction at low temperature. 
Fig. 16 (x32).—After eight days; early stage of reduction. Note 
considerable opacity combined with open siphons. Heart beating, but 
circulation only in right half of the stolon-connexion. Note a new stolonic 
outgrowth into the test of the zooid. 
Fig. 17 (x 64).—A similar zooid after eight days. Débris on siphons, 
which are open. Heart not beating, but visible. 
Fig. 18 (x 64).—Similar; but a slightly later stage of reduction. 
Depressions still mark the siphons. Heart beating, but very faintly. 
Figs. 19-20.—Reduction in KC] solutions. 
Fig. 19 (x25) (50 c.c. sea-water+ 4 c.c. m/2 KCl).—a. Early stage of 
reduction, after one day. Inhalant siphon-lobes of test separate from 
siphons. Outgrowths at the end of stolon. b. The same, twenty-four 
hours later. Cell-strands attach siphon-regions to test. No sign of 
internal organs. Stolon healthy. 
Fig. 20 (x25) (50 c.c sea-water+8 c.c. m/2 KCl). Similar to 19, 6., 
except that the stolon as well as the zooid has been adversely affected 
(shrinkage, cuboidal epithelium). 
Figs. 21-3.—Reduction in KCN solutions. 
Fig. 21 («25).—In m/2,000 KCN. a. Before treatment. The zooid 
is a not quite developed bud. b. After twenty-four hours. Zooid in stage 3 
of reduction. Stolon slightly shrunk, but crowded with cells, and with 
attempts at new growth. 
Fig. 22 (x25).—In m/4,000 KCN. a. Before treatment. 6. After 
forty-eight hours. Zooid much reduced. Stolon crowded with cells, but 
shrunken ; no new growth. 
Fig. 23 (x 25).—In m/32,000 KCN. a. Before treatment. Zooid a not 
quite developed bud. 6. After twenty-four hours. Zooid considerably 
reduced, stolon with clubbed ends and with new growth (within test only). 
c. In reversed position after forty-eight hours. Zocid much reduced. 
Stolon crowded with cells, and with new growth outside test, 
Fig. 24 (x 340).—To show pulsation of stolon. The same stolon-tip 
(a) expanded ; (6) (less than a minute later), contracted. The position of 
