004 Bulletin American Museum of Natural History [Vol. LIII 
changes once more; the tidal movements become very pronounced so 
that extreme brackish conditions prevail, resulting in the development of 
a peculiar mangrove vegetation. The current now keeps mainly to a 
central thalweg, forming one expanse of water 4 to 5 kilometers wide, 
On both banks, however, the mud-flats covered with mangrove forest 
(Rhizophora Mangle Linneus) are cut up by numerous meandering 
bayous, so-called creeks, some of which are 4 to 8 m. deep. On the right 
bank the mangrove swamps thus extend to 12 kilometers north of the 
shore of the main river, the locality of Kunga (Plate LX XV) being situ- 
ated at their extreme northern limit, where they are abruptly bordered 
by a raised, low table land. They are hardly less extensive on the 
southern shore, in Portuguese territory, where they are similarly bound 
in by a low plateau. The mouth itself of the Congo is 10 kilometers wide 
and is comprised between two narrow and low, sandy peninsulas. That 
on the southern, Portuguese shore is much the larger and broader and 
ends in Shark Point which encloses an interior harbor, Diego Bay, shelter- 
ing the port of San Antonio. On its seaward, western side it bulges out 
into the ocean, at Point Padrao (often misspelled Padron), where Diogo 
Cao (Diego Cam), the Portuguese navigator who discovered the Congo 
(or Zaire) about 1484, landed and erected a stone, thus claiming the Iand 
for the Portuguese Crown. Banana Peninsula, on the northern or Belgian 
side, is exceedingly narrow, in many places not over half a kilometer wide. 
It is nowhere more than 2 m. above high tide and at the equinoxes the 
flood from the sea frequently flows over it into Banana Creek. The 
peninsula ends in Banana Point, itself preceded by an extensive spit 
of sand and mud. 
The volume of water carried by the Congo is considerable. John 
Murray! estimated that its mean annual discharge into the ocean was 
419,291 cubic miles, making it second only to the Amazon. It has been 
calculated that at the season of greatest flood it pours 1,200,000 cubic 
feet of water per second into the Atlantic. This fact is mainly respon- 
sible for the current being still perceptible fully 50 kilometers out to sea, 
the greenish-yellow waters being distinguishable from the blue of the 
ocean. Factors of considerable importance to the life of fluviatile mol- 
lusks are the periodical rise and fall of the waters due to the seasonal 
distribution of the rains. This not only produces frequent changes in 
the depth, extent, and volume of the rivers as well as in the strength of 
the current, but it also influences the amount of silt carried by the water 
_ -Murray, J ohn. 1887. ‘On the total annual rainfall and the FORGOR of rainfall to the annual 
discharge of rivers.’ Scottish Geogr. Mag., III, pp. 65-77 
