Silt, clayey 2070 



content 761 



effects 109 



lowered filtering rate 1544 

 , natural 435 



, sandy 738 



Siltation 236, 237 

 Silting 302 



of inlets 1887 



Silty sediments 714, 715 

 Silver 239, 240, 242, 1805 

 Simha's factor 1327 

 Similar 125 



Sinepuxent, Md. 336, 1679 

 Single band 1060 

 Sinuses 85 

 Siphon 534, 1413 



, excurrent 270, 271, 337 



, exhalant 281 



holes of Mercenaria, attracted to 1070 



, incurrent 2154 



, inhalant 281 



length to shell length, ratio of 1720 



, retractile 1440 



, retracting 2007 



, squirting out incurrent 481 



, squirts out incurrent 482 



, stimulate withdrawal of 984 



tubes yellowish 899 



Siphonal apertures 85 



contact 481, 482 



nerve, axons in 2007, 2008 



nerves 254, 984 



, visual receptors in 1052 



photoreceptor system 2007 

 wall, scattered through 



984 



Siphonate bivalves 391 



Siphoning 642 



Siphons 85, 101, 102, 232, 278, 286, 1335, 1352 



, anomalous 1833 



, associated with growth of 474 



, cleansing exposed ends of 996 



, closed 1156 



, closure of 101, 1821 



extended 754 



above substrate 391, 1459 



, extension of 85, 571, 573, 1886 



