36 
posed the name of BhinocrypUsy which is thus a third 
synonym in use. 
Owen seems to have come at once to the conclusion that 
Lepidosiren was not an amphibian, but a fish. His views 
provoked a long controversy, in which every part of the 
structure of each species was minutely scrutinized. The 
reptilian determination was supported by batterer, Bischoff, 
Milne-Edwards, and Grray. Owen at first opposed them almost 
alone, but ultimately gained over to his side all zoologists of 
influence. The old discussion is extinct, and opinion is now 
divided only as to the position of the genus among fishes. 
The Lepidosiren or Protoptenis of Tropical Africa is 
now known to frequent the river Gambia, the Rokelle, 
the Zambesi, and the Nile. All these streams are 
more or less intermittent. When the waters retreat the 
Protopteri which may be left upon the bank bury themselves 
in the mud, leaving however a small aperture for communi- 
cation with the air. As the mud dries and cracks in the 
sun, the fishes become enveloped in earthy cases lined by a 
thick mucous secretion. In this state they remain until the 
return of the rainy season enables them to escape and swim 
about again. The more obvious peculiarities of these curious 
fishes seem to depend largely upon their exceptional vital 
conditions. During the torpid state respiration is carried on 
by the swim-bladders, which temporarily discharge the func- 
tion of lungs, receiving imperfectly venous, and returning 
arterial blood. When the rising of the water permits the 
fish to resume aquatic habits, the gills oxygenate the blood, 
and the swim-bladder receives arterial blood from the 
branchial arteries for nutrition only. The Lepidosiren para- 
doxa of the Amazons is similarly adapted for both atmos- 
pheric and aquatic respiration. 
The characters common to the two genera of Protopteri 
are these: — The skeleton is imperfectly ossified and the 
