PLATYSTERA. 
189 
much closer than either of the three already pointed 
out to Conopophaga, and yet preserving the general 
characters of its own group. The importance of 
such a form is very great, for it not only gives us a 
repetition, even in a sub-genus, of the fissirostral 
type ; hut it brings Platgstera in immediate con- 
junction with Conopophaga, the first group in the 
circle we have been so long in tracing, and the last 
to which we again return. Whether this Platgs- 
tera, which we had named provisionally Lrevicau- 
da, still exists in the National Museum, we know 
not ; but at the time the above note was made upon 
it, that law of variation which renders Platgrhgn- 
chus the raptorial type of the genus Todus, had not 
been discovered; and this explains a part of the 
foregoing memorandum. 
We will now compare the species representing 
the types of form in the suh-genera of Todus and 
Platgstera , and ascertain in what way they resem- 
ble each other. 
Species of Pla- 
tgstera repre- 
senting types 
of form. 
ANALOGICAL CHARACTERS. 
Species of Todus 
representing 
types of form. 
P. longipes. Legs and tail very long T. platydrcus. 
( Bill much depressed, the 1 . , 
P. pedoralis.... ] tip abruptly and strongly V T ‘ ™ la ” 0<x P ha - 
C hooked. j 
P. perspicillata.... A 11 the toes syndactyle T. viridis. 
P. brevicauda Tail remarkably short T. megacepbalus. 
We were perplexed, for many years, in endea- 
vouring to make out why it so frequently happened 
that in very small groups, like sub-genera, there are 
