26 DESIGN IN NATURE 



PLATE XI (conti7iued) 



with D E of Fig. 11, p. 20). The lower right cone (apicial view) shows the double spiral arrangement in a weathered specimen, where 

 the scal'es of the cone are opened out or separated. From photographs taken for the Author by his nephew, J. Bell Pettigrew. 



Fig. 2.— Date palm growing at San Remo, Italy, photographed for the Author by John A. McMordie. Shows double spiral stem, 

 the right spiral being the more vertical and more pronounced. 



Fig. 3.— Date palms growing near that represented at Fig. 2, and photographed for the Author by John A. McMordie, at the same 

 time. In the palm to the left, the left spiral is the more vertical and more strongly marked ; in the right, the right spiral is the more 

 vertical and more strongly pronounced. Better examples of right and left-handed leading spirals cannot he imagined. 



§ 7. Spiral Arrangements in Animals. 



The spiral arrangements in animals are, if possible, more remarkable than those witnessed in plants. In 

 animals the hardest as well as the softest tissues assume the spiral form. The spermatozoa, the ova, the muscles, 

 nerves, feathers, shells, horns, bones, and teeth all attest the prevalence of the spiral as a factor in organisation. 

 Nothing short of design and pre-arrangement and fundamental bias can account for the occurrence of spiral arrange- 

 ments in such a great variety of substances. The presence of spirals in great numbers in plants where there is 

 comparatively little differentiation would have been sufficiently striking, but when we find them in great abundance 

 in the tissues of all animals, even the highest and most complex, we are forced to look for a cause, and to remove 

 them from the category of chance formations. We are obhged to fall back upon Design and Law and Order. The 

 necessity for this procedure becomes imperative when it is remembered that spiral arrangements are not confined 

 to plants and animals, but are also found in molecules, crystals, nebulae, cyclones, sand-storms, water-spouts, 

 whirlpools, &c. 



The spiral formations in animals are not only outstanding and typical but they are bewildering as regards 

 variety and detail. It would be easy to adduce any number in jjorroboration, but it will suffice for the present if 

 I give sufficient to illustrate the"general principle, which I do in the following ten plates (xii. to xxi. inclusive). Further 

 illustrations of an important kind will be found in the body of the work. 



PLATE XII 

 Plate xii. illustrates spiral formations and structures in spermatozoids, umbilical cord, intestine, and nerve cells. 



Fig. 1. Spiral spermatozoon of Crayfish {Astacus fluviatilis) (after Huxley), x850. 



A, B, C, D. Different stages in the development of a spermatozoon from a seminal cell. 



E. A mature spermatozoon — front view. The mature spermatozoon (E) consists of a right and left set of radiating spiral 

 elements seen in the uncoiled state at C. The spermatozoon is bi-laterally symmetrical, and bears a remarkable resemblance to the 

 two sets of spiral nebulfe seen at Plate viii., p. 17 ; to the two .spiral shells .seen at Plate xiii., Pig. 1, D, E ; and to the spiral apex of 

 the heart, .seen at Plate xvii.. Fig. 3, A. The spermatozoon is an embodiment of evolving spiral force (the Author). 



Fig. 2. Spiral spermatozoa of various kinds. 



A. Spermatozoon of Triton (r»'iio» mstefw.f), x 4.'i0. F. Spermatozoon of perch (Per«(_^HOTnh7ts), x 450. 



B. Spermatozoa of rabbit {Leptis cuniculus), x 450. G. Spermatozoon of blackbu'd (Tiir(hif! inerula), x 450. 



C. Spermatozoon of field mouse {Arvicola arviiUs), x 450. H. Spermatozoon of man {Homo sapiens), x 450. 



D. Spermatozoon of wood shrike {Lanins rufiis), x 450. 1. Spermatozoon of frog (liana temporaria), x 450. 



E. Sjiermatozoon of goldfinch {Frhiiplla elegans), x 45(1 J. Spermatozoon of rat (Mvs rafttis), x 450. 

 K. Spermatic cyst of common creeper bird (Gerthia fainiliaris), containing a bundle of .spermatozoa, x 500. 



L. Spermatic cyst of rabbit. «,, The globules, each of which contains a spermatozoon, x 350 ; b, separate globuli, x 500 (after 

 Griffith and Henfrey). 



Fig. 3. — Human umbilical cord, composed of one vein (a) and two arteries (6), intertwining to form a symmetrical left-handed 

 spiral. Resembles spiral water-spout (Fig. 5), and the twining stems of the hop (Plate x., Fig. 2, A). Two spirals at least are 

 necessary to produce symmetry, structures composed of one spiral being incomplete or lop-sided. Drawn from injected specimen in 

 the possession of the Author by C. Berjeau. 



Fig. 4. — tiipnnnUus nudas laid ojien from the .«ide, .showing left-handed spiral inte.stine (a) ; h, anus (after W. Keferstein). 

 Resembles spiral umbdical cord (Fig. 3 of this Plate), and spiral hop stems (Plate x., Fig. 2, A, B). 



Fig. 5. — A. Ganglion cell of a frog, with right-handed .spiral nerve filjres, magnified, a, n, Straight fibre ; b, large coilin" 

 fibie ; r, small coiling fibre (after Lionel S. Beale). Resembles twining plants (Plate x.. Fig, 3, A). ° 



B. Ganglion cell from the .syiupatlieti^ system of the frog, with left-handed spiral nerve fibre magnified, a, Straiu-ht fibre • 

 b, coiling fibi'e, arising by a superficial netting connected with the nucleolus of the cell; c, c, capsule with nuclei (after J. Arnold)' 

 Resembles twining plants (Plate ix., Fig. 3, A and F, p. 22). M 



