COLLECTING 13 



may often be found in dead shells, and, in the South, in holes in 

 the banks. This genus is represented by a number of species, 

 some of which are quite pretty. 



WHARVES AND BRIDGES 



On the piles of wharves and bridges may often be found beau- 

 tiful tubularian hydroids in large tufts just below low-water 

 mark, branched hydroids looking like little shrubs, polyzoans, 

 sea-anemones, mollusks, and ascidians. The species peculiar to 

 these localities are the boring mollusk Teredo naralis, or ship- 

 worm, the boring isopod Limnoria lignorum, and the boring 

 amphipod Glidura terebrans, all of which penetrate the wood and 

 are most destructive. 



The animals and plants of tropical beaches and coral reefs are 

 so various and abundant, so curious and beautiful, as to make a 

 description or even an enumeration of them in a brief space diffi- 

 cult. The collector is bewildered and excited when he first views 

 the profusion of the wonderful forms there found. 



It is not generally known that a fine species of " stony coral " 

 is common from Cape Cod southward, growing in clear water as 

 an incrustation on rocks, and developing little spires as it 

 advances in age. This species, the Astrangia danae, is especially 

 interesting, since it will live in a dish of clear sea-water, and the 

 polyps will expand, showing a very close relationship to the sea- 

 anemone. With care in changing the water this coral will live 

 for days, and may be examined in its expanded condition with a 

 lens of moderate power. 



The most favorable time for collecting on any beach is at the 

 lowest tide, many objects being then uncovered which do not 

 appear higher up on the beach. At the spring-tides, which occur 

 twice a month, at the period of the new and that of the full 

 moon, the ebb is especially low, and affords an opportunity to 

 search for forms whose habitat is below ordinary low- water 

 mark. During storms deep-water forms are often torn from their 

 beds and cast upon the beach. Shore-collecting at these times is 

 often very interesting. 



