An Interesting Experiment. 35 



noting the strange effects occasioned in the mi- 

 mosae, as they drooped their sensitive petioles 

 when disturbed. From the forest he returned to 

 the shores of Botofogo Bay, where he devoted him- 

 self to a study of the invertebrate animals which 

 abounded there. The Planarian worms were a con- 

 stant source of interest, specimens found near here 

 possessing a singular tenacity to life even when the 

 body appeared dead or lifeless, the mouth parts pro- 

 truding as he touched them with his forceps, showing 

 a high state of irritation and vitality. Darwin dis- 

 covered twelve species of these interesting creatures, 

 which he fully describes in the " Annals of Natural 

 History." One of his experiments was to cut a 

 planarian in two parts and devote a certain amount 

 of time to an examination of the several members. 

 For nearly a month he watched a marvellous trans- 

 formation, namely, the formation of two separate 

 individuals out of the single worm. 



The forest in which these worms were found 

 abounded in game, and with an old priest and a 

 native Darwin often wandered far from the ocean. 

 Here he first witnessed the skill with which the 

 natives employed the knife to cut vines and creeping 

 plants. So clever had they become that it was used 

 as the American Indians do the tomahawk, the blade 

 being thrown a long distance with unerring skill. 



Ring-tailed or prehensile monkeys were common, 

 and two of the bearded variety occasioned them no 

 little trouble to capture. Though shot dead, they 

 still clung to the limbs of a lofty tree, and the latter 

 had to be cut down to obtain them — an arduous and 



