—— 
[465] INVERTEBRATE ANIMALS OF VINEYARD SOUND, ETC. 171 
Annelids. 
Page. Page 
PROTONS. VITONIS on acid man 95 cies 463} Clymenella torquata...... 02 edo 
2 RNS Hh 0 Sa ae oe ... 463) Cistenides Gouldii..... on) eo 
Rhynchobolus Americanus. | 463) Sabellaria vulgaris........ BFA | 
R. dibranchiatus .......-... 463; Lumbriculus tenuis........ 463 
TO PODUSHUS «cca ate w ae 4 345; Clitellio irreratus.......... 463 
Seolecolepis viridis....---. 463 Halodrillus littoralis.....-.. 463 
PSMETRLS,.. 2 034 crated dct emieon’s 345 
Nemerteans. 
Page. | Page. 
Meckelia ingens..........- 349| Meckelia rosea ......-.-:.. 350 
MOLLUSCA. 
Gastropods. 
Page. | Page. 
Ilyanassa obsoleta..... .-. 463] Odostomia trifida......... 307 
Tritia trivittata........... 463| Bittium nigrum........-... 463 
Eupleura caudata......... atl | Crepidula convexa: 2... . 24. 463 
Astyris lunata ..-......... 463) Melampus bidentatus...... 463 
Lamellibranchs. 
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Mydarenaria..:...-... 5... 463| Leevicardium Mortoni ..... 358 
Macoma fusea........ ----- 463/ Solenomya velum-..-...-.- 360 
AUSiIUe bOHEP. oo ss +s ooo | Mytilusedulis..:......-.-- 307 
Miomenia SOMMaA...: . =. 2. « 359} Modiola plicatula........-. 307 
Venus mercenaria......... 463)| Peeten irradians .-..-...-- 361 
Ill. 2.—ANIMALS INHABITING THE MUDDY SHORES 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 gene rally covered in summer by 
extensive patches of eel-grass. Over other portions large beds of oys- 
13 V 
