You also want an ePaper? Increase the reach of your titles
YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.
8o DESIGN IN NATURE<br />
PLATE XLIX {continued)<br />
Fig. 7.—Skeleton and outline of man (Homo sapiens). Shows longitudinal and transverse cleavage in arms and legs ; radiating<br />
cleavage in the hands and feet ; and transverse cleavage in the vertebral column and ribs, a, Shoulder joint (universal) ; b, elbow<br />
joint (spiral and hinge) ; c, wrist joint (universal in a way) ; d, hand joints (spiral and hinge ); a, b, humerus ; b, c, radius and ulna<br />
plaited and showing spirality ; c, d, bones of wrist and hand ; e, hip joint (universal) ; f, knee joint (spiral and hinge); g, ankle<br />
joint (universal in a way); h, foot joints (spiral and hinge); e, f, femur; /, g, tibia and fibula; g, /i, bones of foot. The spiral<br />
configuration of the bones forming the human skeleton is given at Plate xix., Figs. 3 and 4 ; Plate xx., Figs. 2 and 4 ; and Plate xxi.,<br />
Figs. 1 and 2. The spiral configuration of the bones of the elephant is seen in Plate xx., Fig. 3.<br />
Fig. 8.—Dissection and drawing by the Author of the wings of the pheasant (Pliasianus colchicus). Shows extreme cleavage and<br />
radiation and large superficial area of the wings. Compare with Figs. 1 and 2 of this Plate. The right wing is extended, and shows<br />
the muscles of the slioulder, the muscles and elastic structures of the wing, and the arrangement of the primary and secondary feathers<br />
in the wing. The left wing is flexed, and displays the skin and elastic structures which assist in folding the wing as corrugated and<br />
puckered. For details of the anatomy of the wing see further on.<br />
PLATE L<br />
Plate 1. illustrates longitudinal cleavage and radiation in the travelKng organs of animals (caudal and<br />
other fins, flippers, feet, wings, &c.), and ho-w intimately these fundamental cleavage arrangements are associated<br />
with locomotion in all its forms.<br />
Fig. 1.—Shows a series of original drawings made for the Author by C. Berjeau in 1867 (vide Trans. Linn. Soc. vol. xxvi.). These<br />
drawings, taken from nature, reveal the important fact that the travelling organs of animals increase in size according as the medium<br />
traversed becomes more and more tenuous and affords less and less support. Thus the feet of the deer, adapted for land transit, are<br />
smaller than the feet of the bird, otter, frog, platypus, seal, and turtle adapted for swinmiing ; these, again, being smaller than the<br />
pseudo-wings of the flying fish, flying lizard, and flying lemur ; the latter being, in turn, smaller than the wings of insects, birds, and<br />
taats adapted for flight. The subjects are arranged with a view to comparison and to facilitate reference.<br />
A. Small foot of deer adapted to land transit.<br />
B. Webbed foot of otter slightly expanded. Adapted for land and water transit.<br />
C. Webbed foot of frog, considerably expanded. Adapted for land and water ; chiefly water.<br />
D. Webbed foot of platypus (duck mole), greatly expanded. Adapted chiefly for water.<br />
K. Webbed hind foot of seal, greatly expanded. Adapted mainly for water.<br />
F. Wings of swallow, enormously expanded. Adapted solely for aerial transit. Compare with foot of deer (A), adapted solely<br />
for land transit.<br />
G. Flippers of turtle, greatly expanded. Adapted almost exclusively for water, a, b, Anterior thick margin; c, posterior thin<br />
margin of fore flipper ; d, e, posterior thin margin of hind flipper.<br />
H. Tail and caudal fin of fish, largely expanded. Adapted wholly for water transit. The fish moves its tail laterally and with a<br />
the vibration occurring on either side of the mesial plane (a).<br />
spiral fignre-of-8 movement ;<br />
I. Tail and caudal fin of manatee (sea cow), greatly expanded as in fish. Adapted wholly for water transit. The tail moves<br />
vertically on either side of the mesial line (a), and makes a figure-of-8 track on the water, as happens in the fish.<br />
J. Portion of body and swimming wing and foot of penguin. The swimming wing is much smaller and stiffer than the flying<br />
wing. It twists and uiitwists in action and forms a beautiful screw (a, b, c). The swimming foot (d) is webbed, and larger than the<br />
un webbed terrestrial bird's foot.<br />
K. Flying-fish with greatly enlarged pectoral fin, which forms a pseudo-wing. It makes short flights, and connects the travelling<br />
organs adapted for the water and the air.<br />
L. Flying lizard with flying membrane (pseudo-wings) supported by its ribs. It glides from heights over considerable distances.<br />
M. The bat with its wings fully extended :<br />
tlie increase in the size of the travelling orgnns (wings) is excessive. Compare with<br />
the foot of the deer (A), the tail of the fish (H), the flipper of the turtle (G), and the flipper of the seal (E). The bat is adapted<br />
exclusively for aerial transit.<br />
N. Flying lemur with flying membrane supported by body, extremities and tail. The flying lizard (L) and flying lemur (N)<br />
connect the travelling organs adapted i'or the land and air. The increase in the extent of the surfaces engaged in transit is very considerable.<br />
Fig 2.—The tail of the herring {Glwpea harengus), drawn by C. Berjeau for the Author, in the closed, semi-closed, and fully<br />
e.xpanded condition. Shows longitudinal cleavage and radiation. The tail is the chief swimming organ, and no better example can be<br />
given of the utility of cleavage and radiation for the purposes of progression. The tail divaricates when making the figure-of-8 movements<br />
in swimming, and so alternately seizes and lets go the water on which the progress of the fish depends. The tail is a finelygraduated,<br />
flexible, elastic structure.<br />
Fig. 3.—The tail of the mackerel {Scomber scomber), drawn by C. Berjeau for the Author, in the closed and expanded condition<br />
Displays the same characteristics as the tail of the herring (Fig. 2).<br />
Fig. 4.—The heterocercal tail of a shark with the caudal portion of the vertebral column terminating in the upper or major lobe<br />
Shows longitudinal and radiating cleavage. The (jrgan, as in the fish, is finely graduated, flexible, and elastic. It tapers from "the root<br />
in every direction. Drawn by C. Berjeau from a specimen in the museum of the Author,