502 MR. J. S. HUXLEY ON THE 
perhaps have said “on a nest”; for the birds may build several 
incomplete nests or platforms before one, finally chosen to be 
the true nest, is finished and laid in. 
From Selous’s observations, the actions and ceremonies con- 
nected with coition are quite elaborate—almost of the same 
order of elaboration as the courtship-ceremonies, though the 
two rituals are completely independent and appear to have 
developed along quite different lines. 
We have already got to know the passive and the active 
pairing attitudes. To complete the description of the mere 
attitudes, it remains to add that, before sinking down into 
the passive pairing attitude (which Selous calls “lying along 
the water’), the birds usually assume a curious fixed and rigid 
pose. I will quote Selous’s words:—“. . . curling his neck over 
and down, with the bill pointing at the ground [weeds], perhaps 
six inches above it, he stood thus, fixed and rigid, for some 
moments (as though making a point) before sinking down and 
lying all along. There was no mistaking the entirely sexual 
character of this strange performance, the peculiar fixed rigidity 
full of import and expression.” 
We must now see how the attitudes are combined in the 
actions themselves. 
In the first place, we have the active pairing attitude and 
the actions associated with it. These actions in pairing have 
been already once described, and they seem to show little 
variation. The bird leaps up, and comes down almost upright 
near the other’s tail. Copulation is then attempted. Selous 
found it hard to decide if such an attempt was successful or 
not. When it seemed successful, the birds apparently uttered a 
louder cry than usual, and afterwards their behaviour had a 
satisfied look. Once, however, when the birds seemed thus 
satisfied, he adds: ‘‘The time occupied was extremely short, 
and one would hardly have thought from the position of the 
two birds that actual pairing had been possible.” In other 
cases he could be fairly sure that the attempt was not successful. 
Whether successful or not, the act always ends in the peculiar 
way already described: the active bird waddles forwards along 
the other’s body, and walks somehow over its head into the 
water, upon which the passive bird raises its neck, leaves the 
nest or platform, and swims away in normal position. 
In the second place, we find that the passive attitude (‘lying 
along”) may take place either on the nest or platform itself, or 
else on the open water (but then apparently never far from the 
nest); the act of pairing itself, however, is possible only when 
the *‘ passive” bird is lying on some firm support. In the second 
place, both cock and hen go into this attitude (the precise attitude 
which the lower bird assumes during the act of coition) indis- 
criminately : Selous’s records give an approximately equal number 
of times for the two sexes. 
However, before trying to draw any general conclusions, let us 
