128 EVOLUTION, GENETICS, AND EUGENICS 



It was sought to break the force of this very serious objection to 

 the theory of special creation by saying that apparently useless organs 

 may nevertheless have functions which are still unknown to us and 

 may be revealed by future discovery. In certain cases, like that of the 

 thyroid gland in the neck, this contention has been justified, but there 

 are many others to which it does not apply. For example, in the great 

 and varied whale-tribe (order Cetacea) which includes the right, or 

 whalebone, whales, the sperm-whales, the porpoises, dolphins, etc., 

 the forelimbs have been converted into swimming paddles, but the 

 hind limbs appear to have vanished completely, leaving no externally 

 visible trace. Internally, however, recognizable remnants of the hind 

 limb-bones may be found in various stages of reduction, which diJQFer 

 in the different members of the order. In the Greenland Right Whale 

 the hip-bone, thigh-bone and shin-bone are indicated; in the Fin whale 

 only the hip-bones and a minute rudiment of the thigh-bone are to be 

 found; in the toothed whales only an almost unrecognizable remnant 

 of the hip-bone is left and in one of the dolphins even that has dis- 

 appeared. Similarly, the snakes have lost their limbs completely, so 

 far as external appearance is concerned, and in most members of the 

 group no trace of limbs is to be found on dissection, but in certain 

 snakes the rudiments of limbs are to be detected. Leaving aside all 

 preconceptions, which is the more probable explanation of such 

 phenomena, the theory of special creation or the theory of evolution ? 



Even if it were admitted that all rudimentary organs and struc- 

 tures found in the adult have a certain unknown use and value, no one 

 could maintain this with regard to the countless instances of structures 

 which are developed in the embryo, but disappear entirely before 

 birth. It is possible to mention but a very few of such instances out 

 of the great number that have already been observed and recorded, 

 but these few will suffice to illustrate the principle involved. 



" Examples of this may be cited from the most widely different 

 groups: in the embryo of insects, especially of beetles, pairs of legs 

 are formed within the egg, not only on the head and thorax, but also 

 on the abdomen, but while those on the head are transformed into 

 mouth-parts, those on the thorax are farther developed in their joint- 

 ing and musculature to be locomotive legs, those on the abdomen are 

 again resorbed. In many fresh-water worms, the eggs of which are 

 laid in a cocoon, from which they are hatched as a finished, minute, 

 crawling worm, larval organs are nevertheless formed, which recall 

 those of the Trochophore,the larva of the original worms, which swims 



