No:2i) (2H BGG OF AMIA AND TTS) CLEAVAGE. 322 
again retreated, this time making short circuits in the adjoining 
grass and frequently thrusting their snouts above the water. 
We now easily ascertained that the party consisted of two 
males and one female.* After a short interval the three again 
returned, when a fierce battle for supremacy ensued between 
the males. They approached from opposite sides of the nest 
and locked jaws in a most ferocious manner. Their struggles 
were so violent that a cloud of muddy water soon arose and 
obscured them from view. When the female, which during the 
battle had remained concealed at the side of the nest, again came 
into view, the victorious suitor rushed at her and began to bite 
her sides with so much vigor that a number of scales were 
detached. The two then swam slowly about the nest, keeping 
their bodies in close proximity. At short intervals this move- 
ment was interrupted by momentary periods of vigorous activ- 
ity. This lasted some five or six minutes, when they departed. 
Believing this to be due to unavoidable movements of the boat, 
we thought it best to retire and leave them undisturbed. 
Returning after twenty minutes, and moving with greatest 
care, we approached and found the male lying at full length in 
the nest. Occasionally he would move slowly around the area, 
keeping up a very rapid movement of the pectoral and pelvic 
fins. We expected that our approach would frighten him ; but 
not until the boat was directly over him did he show any signs 
of vacating. It was now plainly to be seen that the nest was 
filled with freshly deposited eggs. It is probable, though not 
certain, that no eggs had been deposited at the time when we 
first saw the fishes in the nest. The oviposition most probably 
took place after the battle of the males, and during the time 
(5-IO min.) the female was in the nest with the victorious 
male. That the average period of deposition is brief can 
hardly be doubted, since in most cases the eggs of a nest are 
found in the same or nearly the same stage of development. 
In one nest, however, we found some of the eggs in a late stage 
of cleavage, while in others the embryo was already visible. 
* The male is easily distinguished by a dark spot in the upper portion of the 
caudal fin. This spot is fringed by a ring of dull orange, which during the 
breeding-season assumes a brilliant hue. 
