THE SEASHORE 



177 



A Typical Shore Excursion. Long experience suggests 

 two conclusions, a statement of which may be useful. The 

 first is that too much should not be attempted at once. By 

 all means let us welcome every discovery that the young ex- 

 plorers may make even when it puzzles us for the mood of 

 inquisitive research is at the root of all science, and the shore 

 is a stimulating incentive. At the same time, we must make 

 sure that some things are being seen precisely and repeatedly 





FIG. 92. Mermaid's purses, eggs of dog-fish. A, unopened. B, cut open. T, 

 tendrils which twine automatically in the water after the egg is laid and fix it 

 to sea- weed ; e.g, external gills of the unhatched embryo ; d.f y dorsal fin ; y.s, 

 yolk-sac, the nutritive part of the egg enclosed in a membrane ; J/, stalk of 

 the yolk-sac, leading into the food-canal of the embryo. 



so that they enter into a more or less permanent picture of the 

 shore and its fauna. It is well that our reach should exceed 

 our grasp, but let us grasp something. The second is that we 

 must make the transition from observing to interpreting. It 

 is all very well to get to know fifty common shore animals, but 

 this knowledge has largely failed of its purpose if we have not, 

 in the acquiring of it, begun to form the habit of interpreting, 

 of inquiring into the significance of obvious facts in structure 

 and habit and distribution. 



VOL. II. 12 



