Picture - Cosmic Polymath

70 DESIGN IN NATURE
thereof.
PLATE XLIII
Plate xliii. illustrates longitudinal and transverse cleavage and branching generally in plants, animals, and parts
Fio. 1.— Part of longitudinal section of the developing femur of the rabbit, magnified 350 diameters (after Klein and Noble Smith).
Shows longitudinal and transverse cleavage very distinctly, a, Rows of flattened cartilage cells b, greatly enlarged cartilage cells close
;
to advancing bone, the matrix between tliem being partly calcified ; c, d, bone already formed, the osseous trabecule being covered
with osteoblasts (e, e), except here and there, where a giant cell or osteoclast (/, /) is seen eroding parts of the trabeculse fj,h, shrunken
;
irregular cartilage cells ; i, i, vascular loops. The lower half of the figure shows the disappearance of the cartilage cells, the formation
of calcified cartilage matrix, and the deposition by the osteoblasts of secondary osseous substance.
Fig. 2.~Nymphon ahyssorum (after Cuvier). Shows an extreme example of segmentation in body and limbs of deep-sea crab
(after Wyville Thomson).
Fig. 3.—"Dead leaf" insect (Phylliimi sicdfolium, female). Shows resemblance to the venation and branching of leaves in its
flattened body and legs. The peculiarity in form in this insect and in the stick insect (Fig. 6 of this Plate) cannot be explained by
mimicry. Animals have no power to imitate or grow like anything but themselves. Like can only beget like.
Fig. 4.—Egg of fish (Jarrabacm), showing the branching of the vessels in the vitelline circulation (after Dalton).
Fig. 5. Galeodes araneoides, a spider-like animal (family So^mgidx). Shows segmentation of body and great elongation and
branching of the limbs. The limbs might readily be mistaken for small dead branches.
Fig. 6.—The stick insect {Proscopia nodula). So named from its marked resemblance to small dead branches (after Cuvier).
Shows segmentation and branching of body and legs. The peculiar form of this insect cannot be referred to mimicry. It can only
be explained by a common law of development.
Fig. 7. Acacia farnesiana (after Darwin). Aff'ords a good example of branching.
A. Shows the leaves expanded during the day. B. The same folded at night.
Fig. 8.—Portion of leaf of insectivorous plant (Drosophyllam Itisitanicum), (after Darwin). Shows peculiar mushroom-shaped glands.
Fig. 9.—Chara, a plant allied to the Algte (after J. H. Balfour). Shows branching and spiral .formation. The arrows indicate
the direction of the spiral intra-cellular circulation.
PLATE XLIV
Plate xliv. illustrates striking resemblances between the convolutions of the human brain and the hard parts
of certain corals ; also between the hard parts of Venus's flower-basket and the spiral muscular fibres of the left
ventricle of the heart of the bird and mammal ; also between the spicules of sponges and certain crystals.
Fig. 1.—External convolutions of the human brain. Shows folded plicate arrangement.
FlG. 2.—Brain coral (Mseandrina cerchrifomiis), so named from the hard parts of skeleton greatly resembling the convolutions
of the human brain. The resemblance is so striking as to point to a common law of growth. It cannot be explained by mimicry
(photographed by the Author).
Fig. 3.—Transverse section of upper part of tooth of Lalnjrintliodon jaeger), magnified, a, h. Margins of section (after Owen).
Shows a remarkable convoluted arrangement greatly resembling the human brain (Fig. 1 of this Plate) and the brain coral (Fig. 2 of
this Plate).
Fig. 4.—The same tooth : natural size. The centre is the pulp cavity from which the processes of pulp and dentine radiate. The
combined radiation and plaiting and folding of the substance of the tooth is, in a way, unique. The letters a, h, indicate the position
from which the section shown in Fig. 3 was taken.
Fig. 5.—Snow crystals as figured \>\ Scoresby. These are compound branched crystals, the branches being six in number.
Curiously enough the sponge spicules have also, in many cases, six branches or rays. The radiating arrangement is well marked in
both. Here again there seems to be a common law of development.
Fig. 6. — Fertilisation of the ovum of an echinoderm (after Selenka).