240 W. G. Leison— Precipitation and Determination 
mouth, is diminished by the occurence of a Platycerus over it, 
ian ‘according to the third, the same effect is produced by 
the small size of the aperture ‘itself in some instances. It does 
not require much consideration to convince one, that if these 
two ——— are fatal to my views, they are equally so to the 
opposite theory. In C. stelhformis, for instance, the pores 
through which we must suppose the ovarian tubes issued from 
the interior are only large enough to admit of the passage of a 
fine hair. Théy are scarcely visible to the naked eye. The 
tube, under any circumstances, must have filled them almost 
entre. Tf any space at all were left for the passage of a 
am of water through the pore by the side of the tube it 
oun have been exceedingly minute. 
mn weighed as above, therefore, the evidence gives the 
following results :—The first and fourth objections avail noth- 
second and third militate against both theories. But 
when we take into account that in no instance, in the existing 
Echinodermata, where ovarian pores occur, are ‘they at the same 
time oral orifices, the balance seems to be in favor of my view. 
This is all I desire to say upon the subject at present. Although 
I now firmly believe that the valvular orifice in the Cystidea, 
the larger lateral aperture of the Blastoidea, and the so-called 
proboscis of the paleozoic Crinoids are all oro-anal in function, 
yet I shall not maintain that view obstinately against tie 
reason shown to the contrary. 
ART. a butions to Chemistry “ih the Laboratory of | 
o. 12. 
the Lawrence Scientific School. 
§ 1. 
On the precipitation and determination of the metals of the magne- 
stum group in the form of oxalates; by W. Goutp LEISON. 
Pror. Grpss has recently* called attention to the fact that a 
number of metallic oxyds may be completely 9 sa ae eg from 
provided that a 
large excess of alcohol be also added. As it is not easy to 
the res of calcic oxalate precipitated in the ordinary manner. 
The following investigation was ‘ch dlertain for the purpose of . 
testing this method of analysis :— 
* This Journal, xliv, p. 213. 
gespecicnt MM a attos 
a 
