52 ON A GENUS AND SPECIES OF THE CHAKACINES. 
air bladder is about five inches longj by seven-eiohths of an 
inch in greatest diameter, gradually tapering behind the 
middle ; its walls are much thinner and not at all rigid. 
The stomach is filled with parts of various plants, for 
the most part of some broad-leaved succulent cabbage-like 
aquatic plant. In cropping such thick leaves an upper lip 
wonld only be an obstacle. As the npper teeth are flush 
with the outline of the face and include both lower teeth 
and lip when the mouth is closed, the arrangement is ad- 
mirably suited to the habits of the fish. 
Total length sixteen and oiui-fourth, head two and three 
fourths, and depth four and seven-eighths inches. 
Color nearl}' uniform, slightly brownish on the back, 
lightei- beneath, silvery. 
Hah. — Santa Clara, on the Rio Mucury, Brazil, where 
it was secured for the Museum of Comparative Zoology b}' 
Messrs. Hartt and Copeland of the Thayer Expedition. 
The position of this genus in the system is close to the 
genera Tetragonopterui^ and /Scissor. The species is named 
in honor of Dr. Henry Wheatland, President of the In- 
stitute, in token of appreciati(»n of his friendly interest 
and sympathy in favor of ichthyology and ichthyologists. 
