312 DESIGN IN NATURE 



PLA.TE LXXXI (continued) 



active little objects found in the sea. It swims by the aid of cilia ; its movements being steadied by the tvfo tentacles which bear 

 small branches covered with spirally stalked adhesive cells. 



Fig. 5. — Branchlet of Sertularia ahietina — magnified (Guide-Book, British Museum). ((, Polyp ; h, reproductive capsule. 

 Illustrates radiating, globular, and branched arrangements. 



Fig. 6.— a group of Vorticellse magnified 220 diameters (after Marshall and Hurst). 



A, B, C. Show the animal in various positions. 



D. A much smaller specimen drawn to the same scale. 



B. A specimen made to contract by the action of alcohol. 



F. A specimen detached from its stalk and swimming away freely, disc forward. 



G, H, I. Illustrate three stages of fission. 



J, K, L. Show the separated individual swimming by means of the aboral circle of cilia — K being slightly contracted, and L 

 strongly contracted, a, Food-vacuole discharging contents at anus ; '), aboral cilia ; c, cilia of the disc ; c/, contractile fibres of the 

 stalk ; d, disc ; d', disc retracted ; fv, food vacuoli ; jA, pharynx ; jjd, pulsating vacuole ; p, peristoma ; m, myophan striation ; 

 n, nucleus ; v, vestibule. 



The Vorticellfe are remarkable for their beautiful spiral stems and cilia, and the rapidity and grace of their movements. They 

 retract and shorten their stems spirally and suddenly, and elongate them, in similar fashion, slowly. The cilia of the cup-shaped 

 discs are continually in motion, and convey the idea of rotation. The movements of the stems and cilia are voluntary and under 

 perfect control, as any one may readily satisfy himself by careful microscopic examination. The movements are necessary to secure 

 food. They are essentially centrifugal and centripetal, give and take, rhythmic movements. 



PLATE LXXXII 



Plate Ixxxii. shows red and white blood-corpuscles (human) invaded by disease germs ; also rudimentary 

 animal forms. Illustrates spherical, concentric, radiating, branching, segmented, and spiral arrangements. 



Fig. 1. — Diseased condition of the red and white blood-corpuscles in malaria in native children on the west coast of Africa, 

 magnified 1250 diameters (after Stephens and Christophers). 



A. Young form of gamete in red blood-corpuscle. 



B, 0, D. Older forms of the same. 



E. Macrogamete in red blood-corpuscle. 



F. Microgametocyte, ditto. 



G. H. Macrogametes showing punctation of red blood-cells in which they are situated. 

 I, J, K. Types of pigmented leucocytes or white blood-cells met with in native children. 



Fig. 2. — Hydra — a small fresh-water animal found in ponds, ditches, and also running streams; named for its power of recover- 

 ing from injury — the mutilated parts becoming perfect animals. 



A. Hydra or pond weed, natural size. 



B. Section of hydra, greatly magnified, a, Mouth ; b, stomach ; c, ectoderm ; d, endoderm ; e, f, buds ; g, ovary ; h, spermary • 

 i, thread cells (after Parker and Haswell). ' ' 



0. Thread cell, highly magnified (after F. E. Schultze). 



Fig. 3. — Types of Protozoa — Hymnomyxit. 



A. Vampyrella ; B. Mycetozoa ; C. Amoeba ; D. Arcella ; E. Labyrynthula ; F. Actinophrys ; G. Miliolina ; H. Hahomma 

 (after Chapman). 



Fig. 4. — Types of Protozoa — Cortinitn. 



A. Gregarina; B. Monas ; 0. Noctiluca ; D. Vorticella ; E. Podophrya ; F. Ceratium (after Chapman). 

 The Protozoa (Figs. .3 and 4) illustrate radiating, concentric, and branching arrangements. 



Fig. 5.— Vmiu-dht nehnlifera, magnified 100 diameters (after Griffith and Henfrey). Shows the spiral arrangements of the 

 stem by which the animal cautiously and leisurely advances its ciliated bell-shaped body in search of food, and suddenly retracts 

 the same when surprised or alarmed. The mechanism of the spiral stem is a marvel in its way, and thoroughly under control. 



Fig 6.— Joint of stem of Antenmilaria avtmiiwi,, magnified (after Allman). a, Polyp ; h, nematophore ; c, reproductive cap- 

 sule. Shows radiating, branched, and segmented arrangements. i r- i- 



§ 58. Protoplasmic, Amoebic, Muscular, and other Movements. 



In order to obtain an adequate conception of the movements which occur in plants and animals it is necessary 

 to take a wide survey and to study carefully those seen in rudimentary organic substances and structures, such 

 as spores, spermatozoa, plant and animal protoplasm, pseudopodia, ciUa, white blood-corpuscles, the slrcous 

 elements of muscles, the Amoeba, Gromia, Paramecium, Zooids, &c. The movements of the sarcous' elements are 

 especially interesting from their obvious bearing on the respiration, circulation, alimentation, and locomotion in 

 the higher animals. 



Motion is one of the characteristics of matter organic and inorganic alike. Of rest, strictly speaking the uni- 

 verse furnishes no examples. Everything is in motion from the scarcely visible molecule to the great 'heavenly 

 bodies wheeling freely in space. ^ 



