APPENDIX III 313 



from which it is separated by a narrow channel. The 

 portion selected for study is, roughly, about 2-3 acres in 

 extent and is, for the most part, covered with medium- 

 sized boulders. In places, however, these are interrupted, 

 leaving patches of sandy mud. Running parallel with, 

 and close to, low-tide mark for a distance of about 50 yards, 

 is a narrow reef, the top of which just remains uncovered 

 at high water of ordinary spring tides. At the southern 

 boundary of the area a low cliff or bluff makes an abrupt 

 salient in the coast-line. Generally speaking, then, the 

 shore is one of mixed physical character and is consequently 

 well adapted to showing the chief species of plants and 

 animals associated with each of the three types : (i) solid 

 rock, (2) boulders, (3) sandy mud. 



The character of the area can be further made out from 

 the accompanying illustrations. Plate XVI shows the general 

 appearance of the area at low tide and at half-tide ; Fig. 22 

 is a plan ; Fig. 23 shows two sections, mutually at right 

 angles, taken along the paths indicated by the two dotted 

 lines in the chart. The direction of the upper section is 

 due north and south, that of the lower one due east and 

 west, proceeding from low-tide to high-tide mark in each 

 case. 



On the upper section are indicated the names of some 

 of the commonest animals at points corresponding as closely 

 as possible to those in which they were found. Five 

 " positions " are recognised : (i) on weeds, (2) on the upper 

 surface of boulders, (3) on the under surface of boulders, 

 (4) under stones resting on the substratum, (5) in the sub- 

 stratum. It by no means follows, of course, that an animal 

 indicated in any one of these positions does not occur else- 

 where. Some animals, indeed, will be so restricted, but 

 others may be found in as many as four out of the five 

 positions, or possibly even in all five. Generally speaking, 

 however, the mode of occurrence we have indicated for 

 a particular species may be regarded as being the most 

 typical for that species. The species named form about 

 one-half of those found in the course of a few hours 'collecting. 



An important point to be noted in connection with 

 these sections is their trend, relative to the advancing water- 

 line. The upper section runs for the most part parallel 



