INTRODUCTION. 
IX 
b. The fourth toe temporarily or permanently turned backwards, as well as the first. 
Musophagidse. Ramphastidae. 
Cuculidse. Capitonidae. 
Bucconidae. Galbulidae. 
c. The second, third, and fourth toes turned forwards, the first backwards. 
Alcedinidae. Meropidae. 
Bucerotidae. Momotidae. 
Upupidae. Coraciidae. 
d. The first and second toes permanently turned backwards, the third and fourth forwards. 
Trogonidae. 
From this it will be seen that the Trogonidae stand alone in this last group in the 
curious arrangement of the toes. Other differences of internal structure are also observable, 
amongst which may be mentioned the presence of the basipterygoid processes in the skull, 
which are not seen in the other families mentioned above. 
Mr. Wallace, in his admirable paper on a natural arrangement of birds (Ann. N. Ii. 
1856, vol. xviii. p. 197), has the following remarks on the Trogons, which he places in the 
Fissirostral series between the Goatsuckers (though at some distance from the latter) and the 
Jacamars, Motmots, &c. He writes:—“We must observe that many continental ornitho¬ 
logists still place the Trogons among the climbers, because they have their toes placed 
two and two, whereas those of the Kingfishers are arranged as in the majority of birds. 
But this is a point of detail which does not in the least affect the habits ; for the toes 
are in both cases connected together at their basis so as to form a broad sole, giving 
a firm support to the bird without grasping. In both the leg is equally short and weak; 
and in both all the habits depending on the feet are precisely similar. Of how very 
little importance this change in the position of the toes is, unaccompanied by a change 
in their form, motion, or mode of connexion with each other, we may judge from 
the fact of there being species of Kingfishers and of Woodpeckers with only three toes, 
and which yet have no perceptible difference of habits from the rest of the family. It 
