2 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 94 



washing out some of his nematodes from the sand of the bathing 

 beach at Woods Hole, he found copepods among them. Further ex- 

 amination revealed that the sand of that beach and other beaches along 

 Cape Cod and on the neighboring islands was fairly teeming with 

 copepods. Many more could be washed out of the sand than could 

 be obtained by towing along the shore. 



During the following summer the same was found to he true of the 

 sand beaches around Mount Desert Island on the Maine coast. And 

 since every sand beach yielded its quota of copepods, the search was 

 extended to the mud flats, the mussel beds, and the tide pools — in 

 fact, to all kinds of localities where the beach was not composed of 

 solid rock. Let it be remembered that the exceptional tides (12 to 16 

 feet) of the region lay bare immense areas of shore at low water. 

 Every locality examined yielded at least one or more copepod species, 

 usually more, and a few localities as many as 20 or 25. In the mussel 

 beds they were found in the sand or mud beneath the upper layer of 

 living mussels ; in areas covered with seaweed they were in the soil 

 beneath the plants ; in the tide pools they were washed out of the 

 sand or mud covering the bottom of the pool. 



These copepods not only live in the sand and mud while it is covered 

 by the tide, but remain there after the tide has ebbed and left the 

 beach uncovered. As some of them are found as far up on the beach 

 as the average high water mark, the time during which their habitat 

 is covered by the ocean water is very much shorter than the interval 

 during which it is left uncovered. And yet such conditions do not 

 seem to be at all disadvantageous, to say nothing of being inimical. 

 Sand that had remained uncovered at least 10 hours and had become 

 rather warm in the hot sunlight, yielded living and active copepods 

 when washed out in the laboratory. 



Nor are the copepods confined to the beach between tide marks, 

 but are found everywhere in the sand and mud constantly beneath the 

 water down to moderate depths. Portions of the sea bottom brought 

 up on the flukes of anchors or in a dredge usually yield some copepods 

 on being washed out and strained. Many such species have been 

 obtained in dredging and have been described and figured by various 

 authors without the knowledge that they were really sand dwellers. 

 It is of course impossible to tell whether a dredged specimen comes 

 from above or beneath the surface of the ocean bottom. The descrip- 

 tions and figures, however, show just such modifications in size, shape, 

 and structure as appear in these sand dwellers. 



Upon reflection it will appear that two conditions are requisite in 

 order to induce the copepods to penetrate the sand or mud and remain 



