146 



Life 



12: 



Figure 129. Some common 

 animals of rocky shores in 

 southern Cahfornia. I, wave 

 and spray zone: A, Littorina 

 planaxis Philippi, periwinkle 

 ( X 1 ) ; B, ^ cmaea digitalis Esch- 

 scholtz, limpet (xO.5). 



II, high-tide zone: C, Littorina 

 scutulata Gould, periwinkle 

 (Xl); D, Acmaea scabra 

 (Gould), hmpet (xO.5); E, 

 Balanus glandula Darwin, acorn 

 barnacle (xO.7); F, Tegulafu- 

 nebralis (A. Adams), black tur- 

 ban ( X 1) claws of Pagurus sp., 

 hermit crab protruding; G, 

 Pachygrapsus crassipes Ran- 

 dall, common lined shore crab 

 (XO.15). 



III, midtide zone: H, My- 

 tilus californianus Conrad, Cal- 

 ifornia sea mussel (x0.15); I, 

 Nuttalina californica (Reeve), 

 California chitin (xO.3); J, Mo- 

 palia muscosa (Gould), mossy 

 chitin (xO.3); K, Mitella poly- 

 merus (Sowerby), gooseneck 

 barnacle (xO.25); L, Balanus 

 tintinnabulum (Linn.), red and 

 white barnacle (xO.25); M, 

 Tetradita squamosa rubescens 

 Darwin, thatched barnacle 

 (xO.25); N, Bunodactis elegan- 

 tissima (Brandt) (x0.15). 



IV, low-tide zone: O, Antho- 

 pleura xanthogrammica (Brandt), 

 green anemone (xO. 15); P, 

 Spirorbis sp. (x3); Q, Stron- 

 gvlocentrotus franciscanus (A. 

 Agassiz), red sea urchin (xO.35); 

 R, Astraea undosa (Wood), top 

 shell (X 0.1 5). 



this and other Hmpets occupy depressions of 

 the same shape as their shells and as much 

 as 5 mm deep, evidently eroded by the 

 animals. 



The high-tide zone has more species of 

 plants than the top zone, one of which, Pel- 

 vetia fastigiata, a fleshy brown alga, forms 

 large clumps and blankets. Also present is 

 a small bushy red alga Endocladia muricata. 

 A wide variety of other more fragile algae 

 inhabit tide pools of the zone, particularly 

 during the winter when the water is cool and 

 sunlight is not too intense. Common ani- 

 mals are the snails Littorina scutulata and 



Tegulafunebralis. Grazing of these snails on 

 shales frequently produces an intricate pat- 

 tern where the surface has been scraped 

 away; although fragile, such grazing trails 

 have been preserved in the geological col- 

 umn (Seilacher, 1953). Broad flat or gently 

 sloping rocks of the zone are covered by such 

 enormous numbers of small acorn barnacles, 

 Balanus glandula, that in some areas it is 

 impossible to walk without crushing many of 

 them. Locally and mosty on sloping rocks 

 in this zone are several species of limpets, 

 many in their small holes in the rock. Under 

 loose boulders and in cracks live several 



