228 Frerp Museum or Naturat History — Zodxoey, Vor. X. 
ward to Guatemala. Neetroplus panamensis is known only from the 
Rio Chagres, although there are representatives of the genus in Costa 
Rica and other parts of Central America. The last two species may 
be regarded as migrants from Central America. 
The fresh and brackish water representatives of the family Gobiide 
alone seem to have Panama as a center of distribution. They appear 
to have yielded to the different environment of the two slopes and 
only one species, Sicydium salvinit, an upland form, is now common to 
both slopes. Awaous taiasica, Dormitator maculatus, Microeleotris 
mindit sp. nov., Eleotris pisonis and Philypnus dormiior all have very 
near relatives on the Pacific slope, differing sufficiently so that 
usually they can be distinguished quite readily. 
Tue Rio BAYANO AND Its Fauna. 
The Rio Bayano is a broad stream at its mouth and owing to the 
excessively high tides on the Pacific coast of Panama, varying from 
20 to 30 feet between high and low water, the current changes twice 
daily for 30 or more miles up stream. Throughout this entire distance 
the river is broad and muddy, but the head of steam boat navigation is 
not far above the mouth of the Rio Mamoni which empties into the 
main stream about 20 miles from the sea. The lower course of the 
Bayano has large quiet bays where the crocodile is very abundant. 
There are places where on a sunny day an observer may stand in one 
position and count a hundred or more noses of these beasts projecting 
above the water. Many marine species of fishes run up and down the 
lower part of this stream with the tides. 
The Rio Mamoni has a much greater fall than the main stream and 
soon rises above tide level. It then becomes, at least during the dry 
season, a clear stream with a rocky or pebbly bottom. About 10 or 
15 miles above its mouth is situated the town of Chepo which is one of 
the oldest and best known towns of Panama outside of the limits of the 
Canal Zone. During the dry season this stream is quite small at this 
village. It was so low during our visit that we were obliged, in order 
to reach Chepo, to leave our dug-out behind and travel overland the 
last 5 or 6 miles. In this region of savanas this was not difficult. We 
did not explore the stream beyond Chepo, although it extends for many 
miles back into the mountains, and very probably supports forms of 
fishes not obtained by us. 
Following again the course of the main stream for from 10 to 15 
miles above the mouth of the Mamoni another tributary of considerable 
size is reached. This is the Rio Calobre which flows through a densely 
wooded and uninhabited region. The lower portion of this stream is 
