3IO DESIGN IN NATURE 



PLATE LXXX 



Plate Ixxx. illustrates radiating, concentric, spherical, branching, spiral, and segmented arrangements in 

 rudimentary animal forms. 



jTiG. 1. — Amaiha protcus, as seen under var3dng conditions of size and shape (A to J), magnified from 400 to 800 diameters 

 (after Masterman, and Marshall and Hurst). 



A. Amceba in the encysted state, composed mainly of granular and clear sarcode ; c, contractile vesicle ; d, nucleus. It 

 contains an oval-shaped diatom. 



B to J. Different shapes assumed by larger and smaller amoebae. In these figures the contractile vesicle is seen at c ; the 

 nucleus at d, and the flnger-hke projections at e. The projections, sometimes designated pseudopodia, are for the most part conical 

 in shape, as seen at C, D, F, G, H, and I. They are caused by the animal voluntarily forcing a part of its body outwards from the 

 centre centrifugally. They are retracted in an opposite direction or centripetally. They are not due to contractions : if they were, 

 the projections would not be conical-shaped but constricted where united to the body. In reality, they are produced by an 

 aggressive, streaming, rhythmic movement similar to what occurs in the plasmodium of the Mycetozoa and Gromia already 

 described. 



At E, the body (a) of an amceba is stretched over a large diatom (A). 



At J, the varying forms assumed by a small amoeba, at intervals of half a minute, are given. 



Fig. 2, — Foraminifera magnified showing radiating and branched movements in the living sarcode («, h, c). These movements 

 represent lines of force which act in two directions — namely, centrifugally when the sarcode is extended from the mouth of the shell, 

 or through the perforations in the shell into the water to secure food ; and centripetally when the sarcode is retracted and 

 carries the food into the body through the mouth of the shell or the perforations in the shell referred to. These movements are 

 due to vital streaming, as in the Mycetozoa, and are rhythmical in character. They are give and take, come and go, alternating 

 movements, and are voluntary and of set purpose ; the purpose being the securing of nourishment. They are, in no sense, the 

 result of irritability or extraneous stimulation. 



A. Nonioniiia silicea. 



B. Globigerina hulloides (var. friloba). 



C. Miliolina — young specimen (after Chapman). 



Fig. 3. — Polystomella, one of the perforate foraminifera, magnified (after Max Schultze). 



Provides beautiful examples of radiating, branched, and reticulated movements in the living sarcode (pseudopodia), by which 

 food is caught and carried into the interior of the body. The sarcode streams through small apertures in the shell of the animal 

 centrifugally and centripetally. It would be difficult to conceive a more delicate and perfect arrangement for securing food when 

 its minute and fragile nature is taken into account. Some of the captured food is seen entangled in the meshes formed by the semi- 

 fluid sarcode. This foraminifer, like the others already described (Fig. 8, Plate Ixxix.), is endowed with voluntary, centrifugal, and 

 centripetal, rhythmic movements whereby it can extend its sensitive living substance into the water in search of food, and retract or 

 withdraw it into the body as soon as the food is secured. The streaming movements of the sarcode can be timed and regulated 

 by the animal with the greatest nicety. The movements cannot be traced either to contractility, irritability, or extraneous 

 stimulation. 



Fig. 4. — Part of the axis of Isis hippurU, a form of polyp inhabiting the Indian seas. The axis consists of calcareous joints 

 pieced together by horny rings. Shows segmented, radiating, branched arrangements. 



Fig. 5. — Three polyps of red coral in various stages of expansion (after Lacaze-Duthiers). Illustrate radiating, expanding, 

 dilating arrangements, as seen in many flowers, and in the hollow viscera of animals, particularly the heart. The expansion and 

 closing movements are voluntary and time regulated — that is, they occur at certain intervals and in a given order. They are 

 essentially rhythmic in character, and are means to ends. The coral feeds when its polyps are expanded, and rests when they are 

 retracted and closed. The expanding or opening centrifugal, and the retracting or closing centripetal, movements are inherent vital 

 movements, and take place as apart from irritability and external stimulation. 



PLATE LXXXI 



Plate Ixxxi. shows rudimentary animal forms. Illustrates radiating, concentric, branching, spiral, and segmented 

 arrangements. 



Fig. 1.— Red coral "blossoming" (after Lacaze-Duthiers). In this case the polyps are more or less fully expanded They 

 present a stellate, flower-like, symmetrical appearance. They also resemble certain crystals. The coral, as here depicted is an 

 object of great beauty; the solid substance or skeleton of the coral contrasting finely with its delicate filmy-looking polyps 'what 

 is said of Fig. 5 applies also to this figure. 



Fig. 2.— Pentacrinoid larva of the rosy feather star (Antedon bifida)— a kind of star-fish resembling in the young condition 

 the beautiful sea lihes (after Herbert Carpenter). The larva is provided with a long flexible stalk formed of calcareous cylinders 

 In the mature state the stalk is abandoned, and the star-fish creeps freely about the bottom. The body is provided with beautiful 

 slender curled arms, furnished with elegant jointed cirri, by the aid of which and the short ambulacra they secure their food. 



Fig. 3.— Obelia— genus Campanulariidas (Hydroza) ; reproduces itself by free medusiform zooids. 



A. Obelia greatly enlarged (after Parker and Haswell). 



B, C. Medusse of Obelia. 



,r<I^yll^^ T^'y 7!\^^^- i "' ^uT°'l^°P^.'''''' ' ^'Z ?'=*o'i<^f«\' '' mdoderm ; ,/, stomach ; e, generative capsules ; /, horny cups ; 

 ,/ (C), hthocyst ; h (A), medusa bud ; t (B, C, D), manubrium ; ,; (A), three feeding polyps ; k (C), radial canal : I (D) tentacle • m (C) 

 velum. " I \ n 



Fig. i.^CyU/ijir j,li,„wm about twice the natural size (after Chun). Minute form of jelly-fish ; resembles a small o-lobe of 

 transparent glass, from which proceed two long elegant sensitive tentacles or streamers. It is one of the most beautiful and 



