182 



THE BOOK OF NATURE STUDY 



Sacculina protruding beneath the tail, these are among the early 

 exercises on Crustaceans. Nor should one forget to train the 

 eye to find the quaint sea-spiders (such as Pycnogonum littorale) 



which crawl about 

 among the living sea- 

 weeds and hydroids. 



Fortunately there 

 is an admirable guide 

 for the exploration of 

 the haunt we are dis- 

 cussing, Dr. Marion 

 Newbigin's Life by the 

 Seashore* and with 

 this so readily avail- 

 able we need not do 

 more than emphasise 

 our advice not to try 

 too much at once, and 

 to try to interpret as 

 well as to observe. 



One of the charms 

 of this and every other 

 area is the number 

 of unsolved problems. 

 The shore bristles 

 with problems as the 

 rocks with acorn- 

 shells. You cannot 

 go a step without 

 meeting one. Even 

 when no animals are 

 visible, there is the 



FIG. 10 1. A, External appearance of a typical Ascidian. 



B, A dissection, showing I, the inhalant opening ; E, 

 the exhalant opening ; Gn, the nerve-ganglion ; T, 

 the test of cellulose ; Ph, the respiratory pharynx. R, 

 the reproductive organ ; G, the intestine. 



C, i . Free-swimming larva, greatly enlarged, external view. 



D, 2. Longitudinal section of the same. M, mouth ; 

 E, eye ; Br, brain ; Sp, spiracle or breathing aperture ; 

 N, notochord ; Sp.C, spinal cord ; GS, gill-slits. 



problem of where they 

 are. You lift a sandhopper, it lies stiff on your hand, how ? 

 why ? You see the young shore-crabs grey, green, brown, red, 

 and other colours, how ? why ? You find little periwinkles 

 (Littorina rudis), in yellow, orange, brown, red, and other- 



1 See (Newbigin) p. 222. 



