FOOD OF THE OYSTER, CLAM, AND RIBBED MUSSEL. 381 



for the usual rope of the net to be firmly wound around it in order to 

 keep the latter in position. This arrangement allows the use of both 

 net and dredge separately or together with very little trouble or 

 exjiense. When the apparatus is in use, the dredge is drawn along 

 on the bottom in the direction of the arrow, while the net is held about 

 a foot above the bottom and a few feet in front of the dredge, so that 

 the mud stirred up by the latter does not interfere with the net, and in 

 the latter only those objects are taken which are normally suspended 

 in the water passing over the mud bank. 



In order to study the diatoms over as wide an area as possible, 

 collections were made daily from Newport News down to Hamilton, 

 and even from points several miles out in the bay. From these catches 



about 50 species of diatoms were drawn on the spot. For staining the 

 diatoms, the lower algie, and other low forms of life, I employed the 

 method described farther on, which I think offers some advantages 

 worthy of consideration. Several jars full of diatoms were preserved 

 and carried to Baltimore for classification. I have not, however, been 

 able to find a reliable work on the classiflcatiou of American diatoms, 

 and as specialists assure me that such a one does not exist, this plan 

 had to be abandoned, since the time at my disposal just now does not 

 permit me to undertake it. Nevertheless, such a classification would be 

 of great value, and if the necessary collection of diatoms from different 

 points of the American coast could be obtained to enable such a work 

 to be done on a broad basis, it would also pay from a i)ractical stand 

 point. It would be of great interest to so determine the habitat of the 

 different species as to ascertain which grow on the bottom and which 

 are freely suspended in the water. At the same time a careful study 



