1 66 DESIGN IN NATURE 



PLATE LXVI {continued) 



Fig. 11.— Aiiinifilcuk {Podostoma Jiliyerum) with Hagelliferous pseudopodia extended. />, Nucleus ; cv, contractile vesicle, x 2.50 

 (Clap, and Lach.). 



Fig. 12.— Animalcule {Pudostoma fiUcjermn) with pseudopodia retracted. Figs. 11 and 12 illustrate the remarkable power pOHsessed 

 by animalcules of voluntarily changing shape in the absence of nervi-, muscle, or other structure. It will be observed that the 

 extended pseudopodia seen in Fig. 12 are conical at their roots and are not produced by constriction or contraction. J liey are clue 

 to a vital extrusion or pushing out of the living sarcode from within (centrifugal movement), iind cannot be referred to contraction 

 in any form. The appearance presented bv the pseudopodia ^\•hen drawn in or retracted, as seen in Fig. 12, is due to a vital pui^ng 

 together of the sarcode (centripetal moveiiient.) Elasticity plays quite an unimportant part in the pseudopodic movements. Ihe 

 centrifugal and centripetal movements here referred to occur in muscle and in all living .substances capable of changing shape. Ihey 

 are inherent and fundamental, and are the harbingers of the rhythmic movements by which the respiration and circulation are 

 carried on in the higher animals. 



Fig. 13.— Normal animalcule (Reptomomts caudiita) ingesting food by peripheral extension of its body-sarcode. «, Nucleus; 

 cv, contractile vesicle, x 800 (W. S. Kent). The life of the zooid is devoted almost exclusively to feeding ; a remark which applies to 

 most of the lower animals. 



Fig. 14. — Dorsal view of same with short pseudopodal extensions. 



Fig. 15. — Profile view of same. 



Fig. 16.— Animalcule (Mudigamceba simplex) with frustule of diatom attached by sarcode thread, x 800 (\\. S. Kent). The 

 sarcode, which can be extruded and withdrawn at pleasure, can be employed either for seizing or ejecting food. 



Fig. n.—Euchitimia Virchmrii, x 370 (Haeckel). Illustrates concentric and radiating arrangements in rudimentary animal 

 forms similar to those found in crystals, scales of fishes, shells, bones, the transverse sections of plants and trees, and different parts of 

 the higher plants and animals. These concentric and radiating arrangements practically represent lines of force and growth. 



Fig. 18.— Adult animalcule (Noctiluca), donsal view (Huxley). Shows median groove, .stylate rod, and tooth-like process. 

 Fig. 19.— Adult animalcule (Noctiluca), ventral view. Shows oral cavity with tooth-like process, and contained cilium. 

 Fid. 20.— Typical zooids, x 1200. These zooids are fixed, and supply themselves with food by the aid of their flagella, which, 

 swirling about, produce currents which cause the food particles to enter the cup-shaped collar which forms the upper part of the body. 



Fig. 21. — Colony of two zooids {Godosicjafin-nitn) on one pedicle, x 1200 (W. S. Kent). 



Fig. 22. — Free swimming and attached condition of monadiforni germ {Monosiqa rjlobosa) ; the collar and pedicle being not yet 

 developed, x 1200 (W. S. Kent). 



Fig. 23. — A single zooid or animalcule {Gododya allioiiirs), with its body spherically, and its collar conically contracted, x 800 

 (W. S. Kent). Shows centripetal, and, by implication, centrifugal movements in the body and collar of the zooid. The contractile 

 vesicles of the body (cv) execute similar movements. In the zooid three sets of centripetal and centrifugal movements occur ; the one 

 set in the collar, a second in the body, and a third in the contractile vesicles. The voluntary and involuntary movements (funda- 

 mentally rhythmic in character) as witnessed in the higher animals are here clearly foreshadowed, n, Nucleus or endoplast. 



FiG. 24. — A free-floating colony-stock of five zooids (DemnarMa moniliformis) united laterally, x 1000 (W. S. Kent). 



Fig. 25. — Zooid sending out slender pseudopodic processes ; collar and Hagellum extended, n,, Nucleus ; cv, contractile 

 vesicle, x 2000. 



F'iG. 26. — Two zooids assuming an amoeboid condition ; collars and Hagella retracted. Both are sending out pseudopodic pro- 

 cesses, X 2000 (\V. S. Kent). Figs. 25 and 26 illustrate the power possessed by zooids of changing sha]ie centrifugally and centri- 

 petally. This power of changing shape, as explained, is a fundamental endowment in rudimentary animals, and in the tissues 

 (especially the muscular tissues) of the higher animals. 



PLATE LXVII 



This plate illustrates the extraordinary povs^ers possessed by zooids and monads of voluntarily changing shape 

 by centrifugal and centripetal movements, and of reverting to simpler amoeboid conditions prior to reproducing 

 themselves. 



Fk;. 1. — Social colony of zooids (Sdliniujn'ca amphoridium) adhering to confervoid filament, x 625, 



Fig. 2. — One of the same more highly magnified with collar expanded, x 1250. Shows nucleus and contractile vesicles. 



Fig. 3. — Another of same with collar contracted within lorica supported on short pedicle. Figs. 2 and 3 attbrd excellent examples 

 of the power possessed by zooids of opening and closing their collars by centrifugal and centripetal movements. 



Fig. 4. — Another of same encysted within lorica, showing retrogression to amoebic primitive condition. 



Fig. .'). — Another of same with collar retracted, tlagellum protruding and thickened at base, body sarcode projectiii" and lobose. 

 Shows how every portion of the sarcode can cliange shape. 



Fig. G. — Another of .same with filamentous pseudopodia proceeding from top of lorica. 



Fig. 7. — Another of same where the body sarcode has assumed a branched, pinnatified appearance (J. Clark). 



Fig. 8. — Zooid with lorica flatti'iied below and imperfect collar (Biitschli). 



Fi(i. 9. — Zooid (Salpingceca marina) sending out ray-like pseudopodia ; the collar and fiagellum retracted. 



Figs. 10 and 11. — Sarcode ejected from body of zooid assuming stellate form. These figures afford good examples of the power 

 possessed by sarcode of extruding its substance in wedge-shaped masses as apart from contraction and elasticity. 



