INVERTEBRATE ANIMALS OF VINEYARD SOUND, ETC. 465 

 Annelids. 



Iis^ereis vireus 



]Sr. limbata 



Ehyncliobolus Americanus 



E. dibrancliiatus 



Spio robustus 345 



Scolecolepis viriclis 463 



S. tenuis 345 



Page. 



463 



463 



463 



463 



Page. 



Glymenella torquata 343 



Cisteuides Gouldii ... 323 



Sabellaria vulgaris 321 



LumbricLilus tenuis 463 



Olitellio irroratus 463 



Halodrillus littoralis 463 



Meckelia ingens 



Nemerteans. 



Pa^e. 



349 Meckelia rosea 



Page. 

 350 



MOLLUSCA. 



Gastropods. 



Page. 



Il^^anassa obsoleta 463 



Tritia trivittata 463 



Eupleura caudata 371 



Astjris lunata 463 



Page. 



Odostomia trifida 307 



Bittium nigrum 463 



Crepidula convexa 463 



Melampus bidentatus 463 



LameUihrancJis. 



Page. 



Myaarenaria 463 



Macoma fusca 463 



Angulus tener 358 



Tottenia gemma 359 



Yenus mercQnaria 463 



Page. 



Liievicardium Mortoni „ 358 



Solenomya velum 360 



My tilus edulis 307 



Modiola plicatula 307 



Pecten irradians 361 



III. 2. — Animals iNHABiTiNa the muddy Chores and bottoms of 



BRACKISH WATERS. 



The bottoms of the sheltered estuaries, ponds, and harbors, are almost 

 invariably muddy, throughout the greater part of their extent, from low- 

 water mark to their greatest depths, or, in other words, wherever the 

 waves do not act with considerable force. The shores between tides are 

 also muddy in the more protected localities, where the waves do not 

 have sufficient power to remove the fine sediments. The upper and nar- 

 rower parts of nearly all the estuaries in this region are, on this account, 

 muddy, for the rapidity of the tide is seldom sufficient to entirely re- 

 move the fine sediments brought down by the streams. 



A large part of the muddy bottoms is generally covered in summer by 

 extensive patches of eel-grass. Over other portions large beds of oys- 

 S. Mis. 61^ 30 



