470 THE WONDER OF LIFE 



The lampreys have many primitive features, e.g. in 

 their vertebral axis, their skull, their nasal passage, and 

 they are without doubt very old-fashioned types. They 

 probably diverged from the vertebrate stock before the 

 evolution of definite jaws, but it is possible that they long 

 ago lost the jaws which their remote ancestors had. Con- 

 sistent with their old-fashioned character is the poorly- 

 developed brain, and the low order of intelligence that 

 they exhibit. Bashford Dean and R B. Sumner have 

 noticed that many of the movements of brook lampreys 

 are not very * purposelike ', and Hussakof remarks the 

 same defect in the sea-lamprey. ' Thus a lamprey will 

 sometimes pick up a stone outside the nest, carry and 

 drop it into the nest ; or while carrying out a stone will 

 drop it half-way up the side of the nest. It will tug at a 

 large stone which it cannot possibly dislodge, or at a log, 

 in an effort to drag it out of the nest, and will repeat this 

 again and again, without profiting in the least by previous 

 failures. On the whole, one has a feeling that the lamprey 

 possesses a very low mentality, even as compared with 

 fishes '. They seem to be guided greatly by touch, and 

 they exhibit a curious preoccupation with their work, 

 paying no heed, for instance, to onlookers or to the noise of 

 automobiles clattering over a wooden bridge above the 

 nest-building. But whether this apparent absorption in 

 their work may be due to sensory dullness, we do not at 

 present know. In any case, stupid or not, these old-world 

 creatures do not choose the path of least resistance ; alike 

 in their migrations and in their nest-buildings they afford 

 us abundant food for wonder. 



