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IOWA ACADEMY OF SCIENCES. 
Order Ricciace^. 
Rlccia frostii Aust. Not common on mud-fiats on Muscatine 
island in Louisa county. 
E. lutescens Schwein. Very common on mud-fiats on the 
Mississippi bottoms below Davenport, and on Muscatine island 
in Louisa county. 
E. fluitans L. Common in ponds and on mud at Cedar 
Rapids, Forest City, near Davenport, and on Muscatine island 
in Louisa county. Also in Emmet county {E. I. C ratty). 
A SIMPLE INCUBATOR. 
BY E. S. ROSS. 
No claim of originality is made in the presentation of 
the description of the simple apparatus used by me as an incu- 
bator. The idea, so far as I know, originated in the mind 
of Mr. W. D. Frost, assistant instructor in bacteriology in 
the University of Wisconsin. 
The incubator consists of a drygoods box, lined inside and out 
with asbestos paper, set on a galvanized iron base, and divided 
by wire netting into a convenient number of shelves. Heat is 
obtained from a rose burner, and is regulated by a thermostat 
made in the laboratory. The box I used is thirty-three inches 
long, nineteen inches wide and twenty-six inches from front to 
back. The cracks were stopped with rags and then the asbestos 
paper was pasted on the wood. A door was cut in the front, a 
window in one side and one in the door. The door is 25x13 
inches; the side window is 9x8 inches, and the one in the door 
is 12x6 inches. A galvanized iron pipe, three inches in 
diameter, open at the lower end and closed or opened at 
the top by a circular cut-off, passes through the box from the 
base and projects six inches above the top. A hole, three and 
one-half inches in diameter, is cut through the center of the 
lower end of the box and the iron base, leaving only one thick- 
ness of asbestos paper between the chamber containing the 
burner and the lower compartment of the incubator. This hole 
may be closed by a galvanized iron slide. The incubator 
is divided into three compartments, the lower two of which are 
