7 
this latter, a branch of the Cyprinoids, the African Carps and 
Barbels resembling, on the whole, more Indian than Europo- 
Asiatic forms. Its similarity to Australia is limited to the two 
regions possessing. Dipnoous and Osteoglossoid types. But its 
relations to the two other regions of the equatorial zone are near 
and of great interest.” 
And in the affinity of the fresh-water fishes, as regards 
Africa and South America, I must trespass on your patience 
by asking to be allowed to read as follows: 
“The existence of so many similar forms on both sides of the 
Atlantic affords much support to the supposition that at a former 
period the distance between the present Atlantic continents was 
much less, and that the fishes which have diverged towards the 
East and West are descendants of a common stock, which had 
its home in a region now submerged under some intervening part 
of that ocean. Be this as it may, it is evident that the physical 
conditions of Africa and South America have remained unchanged. 
for a considerable period, and are still sufficiently alike to preserve 
the identity of a number of peculiar fresh-water forms on both sides 
of the Atlantic. Africa and South America are, moreover, the 
only continents which have produced in fresh-water fishes, though 
in very different families, one of the most extraordinary modifica- 
tions of an organ—the conversion, that is, of muscle into an 
apparatus creating electric force.” 
The lagoons, or inland waterways, that run parallel to 
the sea, especially on the Guinea coast, presenting, as regards 
their formation, such an interesting geological study, afford 
a grand and rich field for the study of the brackish-water 
fauna, among which are mentioned, so far as I may 
specially give, in connection with the equatorial zone, the 
Razide, S cienide, Polynemida, Caranx, Chatoessus, Megalops, 
and Syugathide. 
Of lagoons I may give here the opinion of the authors of 
‘To the Gold Coast for Gold,’ which is expressed as follows : 
