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312 DESIGN IN NATURE<br />
PLA.TE LXXXI (continued)<br />
active little objects found in the sea. It swims by the aid of cilia ; its movements being steadied by the tvfo tentacles which bear<br />
small branches covered with spirally stalked adhesive cells.<br />
Fig. 5.—Branchlet of Sertularia ahietina—magnified (Guide-Book, British Museum). ((, Polyp ; h, reproductive capsule.<br />
Illustrates radiating, globular, and branched arrangements.<br />
Fig. 6.—a group of Vorticellse magnified 220 diameters (after Marshall and Hurst).<br />
A, B, C. Show the animal in various positions.<br />
D. A much smaller specimen drawn to the same scale.<br />
B. A specimen made to contract by the action of alcohol.<br />
F. A specimen detached from its stalk and swimming away freely, disc forward.<br />
G, H, I. Illustrate three stages of fission.<br />
J, K, L. Show the separated individual swimming by means of the aboral circle of cilia—K being slightly contracted, and L<br />
strongly contracted, a, Food-vacuole discharging contents at anus ; '), aboral cilia ; c, cilia of the disc ; c/, contractile fibres of the<br />
stalk ; d, disc ; d', disc retracted ; fv, food vacuoli ; jA, pharynx ; jjd, pulsating vacuole ; p, peristoma ; m, myophan striation ;<br />
n, nucleus ; v, vestibule.<br />
The Vorticellfe are remarkable for their beautiful spiral stems and cilia, and the rapidity and grace of their movements. They<br />
retract and shorten their stems spirally and suddenly, and elongate them, in similar fashion, slowly. The cilia of the cup-shaped<br />
discs are continually in motion, and convey the idea of rotation. The movements of the stems and cilia are voluntary and under<br />
perfect control, as any one may readily satisfy himself by careful microscopic examination. The movements are necessary to secure<br />
food. They are essentially centrifugal and centripetal, give and take, rhythmic movements.<br />
PLATE LXXXII<br />
Plate Ixxxii. shows red and white blood-corpuscles (human) invaded by disease germs ; also rudimentary<br />
animal forms. Illustrates spherical, concentric, radiating, branching, segmented, and spiral arrangements.<br />
Fig. 1.—Diseased condition of the red and white blood-corpuscles in malaria in native children on the west coast of Africa,<br />
magnified 1250 diameters (after Stephens and Christophers).<br />
A. Young form of gamete in red blood-corpuscle.<br />
B, 0, D. Older forms of the same.<br />
E. Macrogamete in red blood-corpuscle.<br />
F. Microgametocyte, ditto.<br />
G. H. Macrogametes showing punctation of red blood-cells in which they are situated.<br />
I, J, K. Types of pigmented leucocytes or white blood-cells met with in native children.<br />
Fig. 2. Hydra—a small fresh-water animal found in ponds, ditches, and also running streams; named for its power of recovering<br />
from injury—the mutilated parts becoming perfect animals.<br />
A. Hydra or pond weed, natural size.<br />
B. Section of hydra, greatly magnified, a, Mouth ; b, stomach ; c, ectoderm ; d, endoderm ; e, •<br />
f, buds ; g, ovary ; h, spermary '<br />
'<br />
i, thread cells (after Parker and Haswell).<br />
0. Thread cell, highly magnified (after F. E. Schultze).<br />
Fig. 3.—Types of Protozoa Hymnomyxit.<br />
A. Vampyrella ; B. Mycetozoa ; C. Amoeba ; D. Arcella ; E. Labyrynthula ; F. Actinophrys ; G. Miliolina ; H. Hahomma<br />
(after Chapman).<br />
Fig. 4.—Types of Protozoa Cortinitn.<br />
A. Gregarina; B. Monas ; 0. Noctiluca ; D. Vorticella ; E. Podophrya ; F. Ceratium (after Chapman).<br />
The Protozoa (Figs. .3 and 4) illustrate radiating, concentric, and branching arrangements.<br />
Fig. 5.— Vmiu-dht nehnlifera, magnified 100 diameters (after Griffith and Henfrey). Shows the spiral arrangements of the<br />
stem by which the animal cautiously and leisurely advances its ciliated bell-shaped body in search of food, and suddenly retracts<br />
the same when surprised or alarmed. The mechanism of the spiral stem is a marvel in its way, and thoroughly under control.<br />
Fig 6.—Joint of stem of Antenmilaria avtmiiwi,, magnified (after Allman). a, Polyp ; h, nematophore i ; c, reproductive r- capi-<br />
sule. Shows radiating, branched, and segmented arrangements.<br />
§ 58. Protoplasmic, Amoebic, Muscular, and other Movements.<br />
In order to obtain an adequate conception of the movements which occur in plants and animals it is necessary<br />
to take a wide survey and to study carefully those seen in rudimentary organic substances and structures, such<br />
as spores, spermatozoa, plant and animal protoplasm, pseudopodia, ciUa, white blood-corpuscles, the slrcous<br />
elements of muscles, the Amoeba, Gromia, Paramecium, Zooids, &c. The movements of the sarcous' elements are<br />
especially interesting from their obvious bearing on the respiration, circulation, alimentation, and locomotion in<br />
the higher animals.<br />
Motion is one of the characteristics of matter organic and inorganic alike. Of rest, strictly speaking the uni-<br />
verse furnishes no examples. Everything is in motion from the scarcely visible molecule to the great 'heavenly<br />
^<br />
bodies wheeling freely in space.