Vlll CONTENTS. 



PLATYHELMINTHES (Continued). PAOB 



NEMERTINEA 49 



Tetrastemma 49 



NEMATHELMINTHES 51 



Ascaris 51 



Trichina 52 



TROCHELMINTHES 54 



ROTIFERA 54 



Brachionus (A Rotifer) 54 



MOLLUSCOIDA 56 



POLYZOA 56 



Bugula 56 



Plumatella 58 



BBACHIOPODA 58 



Terebratulina 58 



ECHINODERMATA 60 



ASTEROIDEA 61 



Asterias (Starfish) 61 



OPHIUROIDEA 67 



^ Ophiura (Serpent-Star) 67 



/ECHINOIDEA 68 



1 _ Strongvlocentrotus (Sea-Urchin) 68 



HOLOTHUROIDEA ~~'. . . . 74 



Thyone (Sea-Cucumber) 74 



ANNELIDA 78 



CH^BTOPODA 79 



Nereis virens (Clam-Worm) 79 



Lumbricus (Earthworm) 82 



Autplytus cornutus 88 



Lepidonotus squamatus 89 



Diopatra cuprea 90 



Chsetopterus 90 



Amphitrite ornata 91 



Cistenides gouldii 92 



Clymenella torquata 92 



Arenicola cristata 93 



Sabella microphthalma 93 



Hydroides 94 



Spirorbis borealis 94 



GEPHYREA 95 



Phascolosoma 95 



MOLLUSCA 97 



LAMELLIBRANCHIATA 99 



Venus mercenaria (Quahog) 99 



Yoldia limatula 107 



Mytilus or Modiola (Mussels) 109 



Pecten irradians (Scallop) 110 



Ostrea virginiana (Oyster) Ill 



Solenomya 112 



Mya arenaria (Long Clam) 112 



Ensis directus (Razor-shell Clam) , 113 



