WHEN DEVELOPMENT GOES WRONG 133 



whose feet were attached directly to the body, the legs having 

 never developed. 



A great variety of missing parts might be mentioned and 

 specimens innumerable may be seen in almost any museum. ^ 

 One or both horns may fail to develop or the two may fuse into 

 one. A well-known calf in the Chicago stockyards never had 

 but one front leg and was used for years as a '' penholder." ^ 



Men are frequently born minus one or both arms, or parts of 

 the arm, and a student of the writer's, normal in every other 

 way, had no forefinger on the right hand. Almost every neigh- 

 borhood will afford similar examples. 



Not infrequently the nondevelopment of a part becomes a 

 regular and constitutional matter. The male narwhal, for ex- 

 ample, develops the canine tooth as a long, twisted tusk, often 

 attaining a length of seven or eight feet. The peculiarity is 

 that normally only the left tusk develops, the right remaining 

 rudimentary. In rare cases both are developed, btU 7iever the 

 right ivithoiit the left. 



The snake has commonly but one lung, the other regularly 

 failing of development along with his rudimentary legs, which 

 are still represented by a few remains of bones in the pelvic 

 region of such large specimens as the python.^ 



The whale is not a fish but a mammal, like a cow. It is 

 developed from an old-time land animal, and its rudimentary 

 legs are still to be found as parts of the skeleton. Both teeth 

 and hair develop during the fetal life, but are absorbed and 

 disappear before birth, never developing afterward. 



* Abnormalities are sufficiently common and curious to give rise to their 

 special study, which is known as teratology. 



^ A penholder is, in stockyard vernacular, an animal that is used to hold 

 a yard or pen, which, so long as it is occupied, belongs to the owner of the 

 occupant. 



■ Snakes, of course, are developed from prehistoric species with legs and 

 probably at that time supplied with two lungs. The modern lethargic life ren- 

 ders such lung power unnecessary, and the restricted space in the elongated 

 and constricted body makes it also impossible. So the modern snake gets 

 along very well with one lung. 



