330 GLEANINGS FROM NATURE. 



gill openings on each side. The mouth is fitted for 

 sucking rather than biting, and with it they attach 

 themselves to the bodies of fishes and feed on their 

 flesh, which they scrape off with their rasp-like teeth. 

 Later in the season they disappear from these smaller 

 streams, probably returning in mid-summer to deeper 

 water. Thoreau, who studied their habits closely, 

 says of them: "They are rarely seen on their way 

 down stream, and it is thought by fishermen that they 

 never return, but w r aste away and die, clinging to 

 rocks and stumps of trees for an indefinite period ; a 

 tragic feature to the scenery of the river bottoms 

 worthy to be remembered with Shakespeare's descrip- 

 tion of the sea floor." 



A few of the fishes, as the mud minnow and smaller 

 catfishes, together with most frogs, turtles, and sala- 

 manders, on the 

 approach of 

 winter, burrow 

 into the mud at 

 the bottom of 

 FigTioo-Mud Minnow. the streams and 



Umbra K(Kirtland). p O 11 d 8, Or be- 



neath logs near their margins. There they live with- 

 out moving about and with all the vital processes in a 

 partially dormant condition, thus needing little if any 

 food. 



The box tortoise or " dry land terrapin," the com- 

 mon toad, and some salamanders burrow into the 

 dry earth, usually going deep enough to escape frost ; 

 while snakes seek some crevice in the rocks or hole 

 in the ground where they coil themselves together, 



