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.”’ 2 
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 /eft tusk develops, the right remaining 
rudimentary. In rare cases both are developed, dut never the 
right without 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. 
‘1 Abnormalities are sufficiently common and curious to give rise to their 
special study, which is known as teratology. 
2 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. 
3 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. 
