124. S W. Ford—Two new species of Primordial Fossils. 
whose influence we have been able to trace, although we have 
not been able to define them as clearly as we could desire, it 
would be presumptuous in us to express too great confidence 
either in the correctness of our theories or even in the conclu- 
siveness of our experimental results. Of this, however, we feel 
assured, that more trustworthy results cannot be expected from 
a repetition of the same processes until a more complete and 
accurate knowledge has been acquired of the substances em- 
ployed. We have therefore proposed to ourselves a more 
thorough investigation of the haloid compounds of antimony, 
and the first results of this investigation we shall shortly pub- 
lish. After the requisite data have been thus collected, we 
hope to return to the old problem with such definite knowledge 
of the relations involved as will enable us to obtain at once 
more sharp and decisive results than are now possible. 
During the course of this investigation, we have been suc- 
cessively aided in the experimental work by Dr. F. A. Gooch, 
- Mr. GC. Richardson and Mr. W-H. Melville, at the time students 
in this laboratory; and without their assistance we could not 
have accomplished the great amount of labor it involved. 
Harvard College Laboratory, June 12th, 1877. 
Arr. XVI.—Descriptions of two new species of Primordial Fos- 
sils; by S. W. Forp. 
places, and are seen to be thin and delicate. The outer wall 
has been almost wholly removed and the portions of it that re- 
main are much weathered. The material presented for study 
consists, therefore, of the solid moulds of the interseptal spaces, 
the cup filled with limestone, a small number of the septa, @ 
. * This Journal, March, 1873. 
