62 RADULJE 



provided with 1,920 glassy hooks in 160 rows of 

 12 teeth each. 



But it is among the land representatives 

 of the Gasteropoda that we meet with the 

 most astonishing instances of large numbers of 

 teeth. 



Helix Pomatia has 21,000 arranged in sym- 

 metrical order on its lingual band. The large 

 garden slug (Limax maximus) possesses 26,000. 

 A single tooth measures only the 10,000th of 

 an inch ! These numbers, again, are excelled 

 by the Umbrella mediterranea and the Um- 

 brella indica. They seem to baffle calculation. 

 Possibly 750,000 may be somewhere near the 

 truth. 



In the illustrations shown, only small portions 

 of radulse are taken and amplified to about 100 

 diameters. Even these show that the number 

 of teeth on each must be very great indeed. 

 When it is remembered that the foregoing 

 numbers refer to a series of forms curiously 

 carved and sculptured, and the total area 

 carrying them in magnificent regularity is only 

 like that of a coiled-up wateh-spring, we must 



