220 DESIGN IN NATURE 



squirrel is provided with a flying membrane which extends between its fore and hind Hmbs ; and the flying lizard 

 is provided with a similar membrane, which is supported by its ribs. The galeopithecus, and flying hzard, how- 

 ever, have nothing in common, and no direct connection either with the pterodactyl or with the bird. Similarly, 

 the pectoral fins of the flying fish do not connect that animal with the galeopithecus, flying Uzard, pterodactyl, 

 bird, or bat. This modification of hmbs for the purposes of progression opens up a wide question quite apart from 

 evolution and descent, and even classification. The dolphins (sea mam.mals), if the pectoral fins be excepted, have 

 no hmbs : the whales have pectoral fins or flippers, but no posterior hmbs or the merest vestiges of them. 

 The same is to be said of the Sirenida (the dugong, manatee, rhytina, &c.), where the flippers bear a general resem- 

 blance to limbs. All these animals (mammahan in type) are supphed with swimming tails and fish-Uke bodies. 

 In the case of the seal, sea-hon, and walrus (likewise mammals), they are furnished with more or less fish-shaped 

 bodies, and modified but well-developed limbs, each of which has five digits. The digits support a swimming 

 membrane, and can be opened and closed, particularly those of the posterior hmbs. The digits and swimming 

 membrane of the hind limbs form what is virtually a powerful swimming tail, which, as in the fish, is lashed from 

 side to side, and is the chief organ of propulsion. In the sea-mammals the tail is lashed in a vertical direction. 

 In the flying fish the pectoral fins, which are the homologues of the anterior extremities, are greatly expanded, 

 and have the form of wings, and act as such to a hmited extent. The flying fiish has, in addition, a swimming tail, 

 and forms a connecting hnk between progression in the water and the air, just as the galeopithecus and flying 

 lizard form connecting links between progression on the land and in the air. In all these cases, the construction 

 of the hmbs (designed and modified, as explained, for particular purposes) affords no proof of evolution. Indeed, 

 and as already stated, the several travelling organs are constructed in the young animals before they are required. 

 As a matter of fact, the animals whose limbs and travelling surfaces are modified and adapted to operate on essen- 

 tially different media must be arranged in different categories, as they include, or may include, insects, fishes, 

 reptiles, birds, mammals, &c. That the modifications referred to have nothing to do with descent and evolution 

 as their chief factor, is proved by the changes which occur in the frog during development. In the tadpole state 

 it is provided with a swimming tail adapted for propulsion in water ; as it reaches the adult condition its tail dis- 

 appears, and it is furnished with four hmbs, each having five digits, with a swimming membrane adapted for water 

 and land transit. The travelling organs are modified to meet the requirements of the water and land respectively, 

 but the water and land and environment do not make the travelling organs ; these are designed, specially pre- 

 pared structures connected with the movements, habits, and breathing of the animal. 



The question of hmbs as organs of locomotion is a very wide one. The shape of limbs, if it proves anything, 

 proves design as contra-distinguished from evolution. When we find animals of every conceivable kind modified 

 to meet the particular requirements of transit on the land and in the water and air, design of necessity takes 

 precedence of evolution. The transitions of structure and function in the organs of locomotion in animals a.re 

 very numerous, but they are, in every case, graduated and designed transitions : they are adapted to the land, 

 the water, and the air, or partly the one and partly the other. They are in every case means to ends. They 

 are never chance products. 



Small feet suffice for supporting heavy animals on land. The deer, ox, horse, pig, &c., afford examples. Large 

 feet, often webbed, are required for soft or boggy land, as witness the feet of the frog, wading bird, ornithorhynchus, 

 otter, beaver, &c. Still larger travelhng organs are required for the water, as seen in the flippers and feet of the 

 turtle ; the feet and swimming tail of the newt and crocodile ; the fins and tail of the fish ; the webbed hands and 

 feet of the seal, sea-hon, and walrus ; the flippers and swimming tail of the dolphins and whales ; the fin-like 

 anterior extremities and fish-hke tails of the dugong, manatee, rhytina, &c. 



Lastly, very greatly expanded travelling organs are required for transit in the air. These are seen in the 

 extinct flying reptiles and in modern insects, birds, and bats. Then there are, as stated, transition hnks in the 

 travelhng organs, as between the land and air on the one hand, and the water and air on the other. The flying 

 lemur, flving squirrel, and flying Hzard afford examples of the former, and the flying fish of the latter. 



I purposely abstain from an enumeration of the myriad travelhng organs in the infusoria and lower animal 

 forms, and in plants. With such an amazing array of designed and adapted travelhng structures occurring in 

 innumerable animals, and in not a few plants, it is impossible to come to any other 'conclusion than that all 

 animals, and all plants with independent movements, are specially designed and constructed organisms as apart 

 from evolution. As environment and externahties do not form the organs of locomotion, neither do they fonn 

 other organs in plants and animals as a whole. 



The subject of the modifications of hmbs, and especially those of the horse, is not a fortunate one as proving 

 the truth of the doctrine of evolution. Even in animals so far advanced as the vertebrates, hmbs can be dis- 

 pensed with. The serpent has no hmbs, and some of the hzards have the merest traces of them ; but both 



