208 



Index 



sex characters, secondary, evolution 



of, 53 

 shark, blood, 117 



salt tolerance, 76 

 shrimps, brine, 71, 73 



gill cavities, 98 



in brackish water, 31 



in Elba estuary, 28 



in Ganges delta, 27 



in lakes, 42 



in Sahara reservoir, 43 



in salt marsh, 33 



in Thames estuary, 28 



kidneys, 123 



reproduction, 133 

 siphonarians, water-breathing, 96 

 Siren, respiration, 106 

 skin of vertebrates, respiration, 10 

 slugs, mucous covering, 94 

 smelt, grunion, 66 



snails (see also gastropods, mol- 

 lusks) 



air-breathing, 60 



as colonizers, 10 



body fluids, 112 

 snails (Continued) 



branchiate, 34, 60, 93 



desiccation, 89 



eggs above water, 62, 63 



fresh-water, in estuaries, 26 



gill cavities, 98 



in deserts, 16 



in salt marsh, 33 



integument, 100 



land, eggs, 62 



limnaeid, 27 



locomotion, 125 



migrate to land, 21 



on beaches, 65 



pulmonates, 34, 60, 93, 96 

 salt toleration, 71 



reproduction, 134 



respiration, 109 



salinities, 43 



size, 73 



veliger larvae, 8 



viviparid, 27 



zonation, 86 

 snakes, on Krakatao, 46 

 sodium, in sea water, 4, 73, 77, 114 

 soil, 9 



animals, 38 



protozoa, 93 

 ^olenidae, 27 

 solubility of gases, 34 

 Spartind, beach zone, 19 

 spermatophytes, 56 



as food, 136 

 Sphderoma rugicdudd, 30 

 spiders (see also arachnids) 



eaten by gobies, 58 



in caves, 39 

 sponges, boring, 38 



cell membranes, 115 



in Ganges delta, 27 



largely marine, 93 



succession, 52 

 spreading, 50 



Squdlus suckleyi, salt tolerance, 76 

 stability, of ocean, 13 

 starfish, body fluids, 112 



larvae, 139 



oxygen used, 58 

 stenohalin animals, 95 



fishes, 97 



oysters, 74 



