294 BULLETIN: MUSEUM OF COMPARATIVE ZOÖLOGY. 
turbid mixture poured into the pan on the glass and left overnight. 
The slimes settled on the glass in a layer about 4 inch (.013 m) deep. 
The slime-covered plate was removed and supported at a tilt of 20 
degrees, one end resting on a brick, the other on a sheet of slate. A 
portion of the lower edge of the model fell off abruptly, the remainder 
rested on the slate, which was horizontal. ‘The sprays from the atom- 
izers were now turned on and in two hours the drainage pattern 
SN 
EN 
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y 
Fig. 2. Slime model, First stage. Sprayed with atomizers. 
Tracing of Plate 5, fig. 1. 
shown in Plate 5, fig. 1, was produced. Continued spraying pro- 
duced more mature topography, with deeper canyons on the side 
of the steep fall-off and flood-plains at the mouths of the rills on the 
opposite side. (Plate 5, fig. 2.) 
An analysis of the drainage in Plate 5 shows a number of rhythmic 
features (Fig. 2). The model differs from those of Plate 1 in that the 
