DARWIN'S WANDER-YEARS 47 



in itself a sufficiently pointed and remarkable phe- 

 nomenon. It was here, too, that he first saw that 

 curious animal, the Tucutuco, a true rodent with the 

 habits of a mole, which is almost always found in a 

 blind condition. With reference to this singular 

 creature, there occurs in his journal one of those inter- 

 esting anticipatory passages which show the rough 

 workings of the distinctive evolutionary Darwinian 

 concept in its earlier stages. c Considering the strictly 

 subterranean habits of the Tucutuco,' he writes, 'the 

 blindness, though so common, cannot be a very serious 

 evil; yet it appears strange that any animal should 

 possess an organ frequently subject to be injured. 

 Lamarck would have been delighted with this fact, had 

 he known it, when speculating (probably with more 

 truth than usual with him) on the gradually acquired 

 blindness of the Aspalax, a gnawer living under the 

 ground, and of the Proteus, a reptile living in dark 

 caverns filled with water ; in both of which animals the 

 eye is in an almost rudimentary state, and is covered by 

 a tendinous membrane and skin. In the common mole 

 the eye is extraordinarily small but perfect, though 

 many anatomists doubt whether it is connected with 

 the true optic nerve ; its vision must certainly be im- 

 perfect, though probably useful to the animal when it 

 leaves its burrow. In the Tucutuco, which I believe 

 never comes to the surface of the ground, the eye is 

 rather larger, but often rendered blind and useless, 

 though without apparently causing any inconvenience to 

 the animal : no doubt Lamarck would have said that the 

 Tucutuco is now passing into the state of the Aspalax 

 and Proteus.' The passage is instructive both as show- 



