HISTORY AND NATURAL HISTORY 35 



along the Patagonian coast for as much as three hun- 

 dred miles. 



At Woods Hole, on Cape Cod, I have at certain 

 seasons dipped up a bucket of sea water from the 

 harbor and found more space occupied by clear, 

 jelly-like ctenophores, each the size of a walnut, 

 than was taken by water. Sometimes I have dipped 

 up a fingerbowl of sea water and found it so filled 

 with small pin-point-like copepods that again there 

 seemed to be more of them than of the water itself. 

 These tiny relatives of the lobster-krills are also the 

 food of whales, and they, too, may discolor the 

 ocean for miles. 



Around bodies of fresh water, may-flies or midges 

 may emerge in clouds. At Put-in-Bay, near the 

 lights flooding the monument that commemorates 

 Perry's victory, I have picked up living may-flies by 

 the double handfuls from the millions that fly to- 

 ward the lights; and near by our lake boat steamed 

 through windrows of cast skins of the emerging may- 

 fly nymphs. Nearer Chicago I have taken water 

 isopods, the half-inch crustaceans mentioned earlier, 

 by the bucketfuls from pools where they had col- 

 lected in numbers only to be compared with those 

 in twenty swarms of bees. 



We have already spoken of the migratory hordes. 

 Locusts in migration (116) swarm out of the sky in 



