626 JAMES L. KELLOGG 
the function of food collection, and of the disposal of undesirable 
material, in some detail (‘Shellfish industries”). The volume of 
material was there shown to be the determining factor in the 
disposal of collections. 
Mr. J. H. Orton, in 1912, published observations on the feed- 
ing of lamellibranchs, giving particular attention to the function 
of the gills, in several forms, but noticing, also, some features of - 
mantle ciliation. 
So far as I am aware, these accounts are the only ones which 
refer to a ciliary mechanism for the removal of foreign matter 
from the mantle chamber. 
The mechanism for the removal of objectionable material, 
brought into the mantle chamber of bivalves by the incurrent 
stream, was first seen by the writer, in Yoldia, in 1898. Since 
that time, all the coasts of the United States have been visited, 
as many as possible of their lamellibranchs being studied, until a 
very large amount of material has been collected, much of which 
should have been published earlier. Observations on the col- 
lection and ingestion of food have been made at the same time, 
and the present paper gives a brief account both of the col- 
lection of floating material, and of its disposal, in the more 
interesting of the forms in which the mechanisms have been 
studied. It is also the aim here to illustrate in the figures, fea- 
tures of the gross anatomy of several forms, especially from the 
Pacific, which have not previously been described. All obser- 
vations are recorded as fully as possible in the figures, and they 
are depended on to give much of the information collected on 
anatomy and ciliation, which is not recited in the text. 
METHODS 
Powdered carmine has universally been used to demonstrate 
currents caused by ciliary action. It*was often useful here, but 
its grains are very small, and it is so light that small quantities 
are directed to a desired point with difficulty. It also floats in 
water currents produced by cilia, and then does not always follow 
the course taken by objects actually resting on the ciliated sur- 
a 
