376 BRITISH BIRDS. 
Family CUCULID, or CUCKOOS. 
The Cuckoos are a large group of birds presenting great diversity of 
general appearance, but fairly well defined from their allies, the nearest of 
which are probably the Musophagide, or Plantain-eaters, of the Ethiopian 
Region. Sclater associates them with the Woodpeckers, Kingfishers, 
Swifts, and other Picarian families ; Gadow regards them as a connecting- 
link between the Pheasants and the Picarian birds; whilst Forbes placed 
them amongst the Pheasants, Bustards, and Rails, on account of the 
presence in the latter groups of birds of the ambiens muscle. Like the 
Passerine birds, they have only one notch on each side of the posterior 
margin of the sternum; but their pterylosis is said not to be Passerine in 
character, though very variable. Huxley associates them with the King- 
fishers, Hoopoes, Bee-eaters, and Rollers. Gadow says that in their 
digestive organs they most resemble the Bee-eaters, Rollers, and Goat- 
suckers. 
The true Cuckoos moult twice in the year, in spring and autumn; but 
whether this be the case with the more distantly allied genera I am unable 
to say. 
The Cuckoos may be divided into numerous subfamilies presenting great 
variety of appearance, and scarcely possessing any external character in 
common except that of having two toes in front and two behind. In the 
true Cuckoos, or Cuculine, most of the species show great superficial 
resemblance to a Sparrow-Hawk, especially in their long and somewhat 
rounded wing, which contains ten primaries, and long graduated tail, 
composed of ten or twelve feathers. The shape of the bill somewhat 
resembles that of the Thrushes. | 
There are about 180 species of Cuckoos, belonging to various genera, 
which are distributed all over the world, except in the Arctic regions. 
Two species only are found in Europe, one of which is a regular summer 
visitor to our islands, and the other is said to have visited them once. 
Two American species are also said to have accidentally strayed as far as 
Treland. 
Genus CUCULUS. 
The genus Cuculus was recoguized by Linnzeus in the twelfth edition of 
his ‘Systema Nature’ (i. p. 168), published in 1766. C. canorus (the 
Cuculus cuculus of Brisson) is the type. 
