1 8 MEMOIRS OF THE NUTTALL ORNITHOLOGICAL CLUB. 



CHAPTER III. 



THE SAND BEACHES AND THEIR BIRDS. 



"At full of tide their bolder shore 

 Of sun-bleached sand the waters beat ; 



At ebb, a smooth and glistening floor 

 They touched with light, receding feet." 



Whittier, " The Tent on the Beach." 



The four long sand beaches on the northeastern coast line of the County 

 are favorite resting and feeding places for birds. This is particularly true of 

 Ipswich and Coffin's Beaches which are broad and flat, and are bordered in 

 places by sand bars. The beach at Plum Island is for the most part of a 

 different character, shelving abruptly into deep water. 



Although the number of marine invertebrates on beaches is much smaller 

 than on a rocky shore, some live in the sand, and many more — some from 

 deeper water, some from the nearby rocky coasts, — are cast up on the beach, 

 and serve as food for Gulls, Crows, and other birds. A few of the common 

 and important marine invertebrates found on the beaches are the following : 

 finger sponge {Chalinopsilla oat lata), jelly-fishes (Aurelia flavidula and Cyanea 

 arctica), under the huge disk of the latter being often found small Crustacea 

 {Hyperid). The common clam-worm {Nereis) burrows in the beaches but is 

 more abundant in the protected inlets and creeks. Starfishes {Asterias vul- 

 garis) and brittle-stars {Opliiopholis aculeata) are found commonly among the 

 rhizoids of the Laminaria. 



The sea-urchin {Strongylocentrotus drobachiensis), an animal washed from 

 rocky stations, is sometimes found, while the sand-dollar {Echinarachnius 

 parmd) is common near low-water mark, slightly buried in the sand, revealing 

 itself by a circular prominence. The hermit crab {Pagurus bernhardus) occu- 

 pies old snail shells at low-water mark but is more common in the inland 

 creeks. The green crab {Carcinus mcenas) belongs south of Cape Cod, but it 

 appeared on this coast in 1901 and increased rapidly, not only on the shores, but 

 especially in the. estuaries and creeks. The severe winter of 1903-4 has appar- 

 ently exterminated it here, for none could be found during the following sum- 

 mer. Rock crabs {Cancer irroratus and C. borcalis) abound, especially the 



