210 



INDEX 



Snail, see Land snail. 



Sow-bug : external parts, 40 ; append- 

 ages, 41. 



Spongiaria, 161. 



Squid : external anatomy, 113 ; mantle 

 cavity, 115; excretory system, 117; 

 circulatory system, 119; respiratory 

 system, 119; digestive system, 120; 

 reproductive system, 122 ; nervous 

 system, 123; pen, 124. 



Starfish: external parts, 131; digest- 

 ive system, 135 ; reproductive sys- 

 tem, 135 ; ambulacral system, 136 ; 

 nervous system, 137; circulatory 

 system, 138. 



Strongylocentrotus, 139. 



Sycon sponge, 161. 



Taenia crassicollis, 74. 

 Taenia saginata, 74. 

 Taenia serrata, 74. 



Talorchestia, 42. 



Tapeworm: external form, 74; proglot- 

 tides, 75 ; encysted tapeworm, 77. 



Tubularian hydromedusan : alterna- 

 tion of generations, 149 ; hydroid 

 stage, 149 ; medusoid stage, 153. 



Tunicata, 125. 



Turbeharia, 70. 



Unio, 83. 

 Urochorda, 125. 



Venus mercenaria, 93. 

 Vorticella: general form, 168; repro- 

 duction, 170; conjugation, 171. 

 Vorticellidse, 168. 



Wasp : external parts, 1 ; mouth-parts, 

 11. 



Zoothamnium, 168. 



