278 THE AMERICAN MONTHLY [Oct 
numbers of frustules of different kinds found in the stom- 
ach and intestines, were diatoms, the outer shells of which 
being composed of almost pure silica, are well-nigh in- 
destructible by the digestive process, fire, or the strong- 
est acids. 
After preparing the diatoms for examination under the 
microscope, it was seen that the greater part of these 
_ small organisms in view were Navicula of small size, of 
the type known as radiosa, arenaria, etc., of two or three 
sizes, or of the lanceolata form, with divergent striv, such 
_as are figured in Schmidt’s Atlas of the Diatomaces (plate 
47) or varieties of that type. Somewere much larger and 
some smaller, but mostly of the same general type. 
Gomphonema was, as usual in Kausas gatherings, very 
rare, though four or five species were met with. Cym- 
bella, also one of the commonest forms anywhere Hast, 
was equally scarce ; and I had about concluded that none 
except small forms were present, when I unexpectedly 
came across an Amphiprora of the largest size, and of a 
decidedly rare variety, not found in the forty-four Cin- 
cinnati slides. The individuals of this family are among 
the largest diatoms; and they were remarkably abundant, 
as if there was a savor or a large body of nourishment in 
them which had especially appealed to the fish’s taste. 
A noticeable thing was not only the abundance of this 
large and rare Amphiprora not found at Gage’s pond or 
Silver Lake, but the remarkably large numer of fine 
Pleurosigma, mostly spencerwi or. varieties, every field 
containing at least one and often several. 
An unusually large form of Amphora lineata, not found 
at Gage’s pond, Silver Lake, or in the forty-four slides 
of Cincinnati diatoms, was quite abundant. Only one 
Navicula of the rhomboides type was seen, and that was 
_a variety, the Colletonema vulgare of Thwaites. Stauro- 
neis phenicenteron, one of the few distinctively fresh 
water forms said to be found everywhere, was not met with: 
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