8 L. W. SACKETT 



with roughened skin where the quills would probably have first 

 appeared. Claws were hard and perfectly formed, rudimentary 

 thumb not appearing even in a callous scar. The soles of the 

 feet were warty as in the adult. The bones were hard but not 

 completely calcified. The teeth appeared only as soft buds or 

 swollen places on the gums. Sex organs were dimly discernible. 

 The external ear was perfectly formed and open into the tym- 

 panum. The eye slits and nasal passages were open. Vibrissae 

 were wanting, or were very slightly differentiated. This indi- 

 vidual's development may not have been normal, but it is 

 more probable under normal than above normal. 



There were some marked differences in the case of the other 

 two infants. They were somewhat larger and longer. The 

 vibrissae were grown. The teeth were through and fully enam- 

 eled. What is most significant is that they were covered with 

 very hard, sharp, barbed quills from the point of the shoulders 

 to the top of the head and from the middle of the back to the 

 tip of the tail. There was a region along the back of about 

 one and one-half inches where there were no quills. Whether 

 this shows any atavistic tendencies is not certain since the 

 geological history is not well known. The high development of 

 the foetus taken with the fact that the mammary glands of 

 the mothers showed no signs of swelling preparatory to giving 

 suck, suggests that the Indian belief referred to by Brehm (5) 

 may have some foundation of fact. In speaking of the " Unk 

 Wunk," the Indian legend says: "The mother (porcupine) has 

 no teats, furthermore the young cannot suck, and consequently 

 the mother is accustomed to drive the young from her imme- 

 diately after their birth and thus force them to begin their 

 hard gnawing work from the first day of their lives." 



The story may or may not be founded on fact, but these 

 young porcupines dying before actual parturition were physi- 

 ologically equipped for climbing and gnawing, from the day 

 they should have been born. The question at once arises, if 

 this early independence is as evident as the legend and as the 

 physiological maturity would suggest, how will this affect the 

 psychic life of the animal? Will the porcupine prove to be 

 like the guinea pig with its great precocity and its limited ability 

 at maturity, or like the rat which is helpless and almost sense- 

 less at birth but which shows a high degree of plasticity in later 



