DISTRIBUTION OF ORGANISMS. 189 



ment we may suppose to be connected in some way with the 

 early history of the whole group of species a family or clan 

 sacrifice, as it were, for the benefit of a less fortunate mem- 

 ber. Thus, it will be observed, when we take the whole 

 group together, as only variations produced by certain na- 

 tural laws from one stock, the parasitical reproduction of the 

 cuckoo sinks into that character which alone we can reconcile 

 with the rest of the providential scheme, a trivial exceptive 

 evil in the midst of much that appears, and undoubtedly is, 

 very good. 



The Jay is said by Professor Macgillivray to connect the 

 crows with the Tits (Paridd), a varied genus of notedly 

 crow -like characters. 



From the Nutcracker, another of the smaller crows, come 

 the Woodpeckers (Piddai), which present merely a modifica- 

 tion of the corvine structure to suit an insect-eating life 

 amidst growing timber. The woodpeckers, for this purpose, 

 have turned back the outer toe, so as to be able to climb and 

 cling to the stems of trees ; the beak has been at the same 

 time elongated, to enable them to search in the crevices of the 

 timber for insects. They are spread into all the quarters of 

 the globe. It is interesting to observe the kindred nature of 

 the parent species : the nutcracker is often observed to climb 

 the bark of trees ; it uses the beak to split open nuts ; and, 

 as in the woodpecker, the middle feathers of the tail have 

 been found worn in consequence of their climbing habits. 

 In near affinity to the woodpeckers, but perhaps only in 

 cousinship, not in descent, we must place the Creepers (Cer- 

 thiadiE), nut-hatch, hoopoe, wren, &c. ; smaller birds, which 

 have the toes in the usual arrangement, but are not less dex- 

 terous in making their way along the bark of trees, and 

 searching it for their favourite food. The Trogons of India, 

 Africa, and America, and the kindred Todies, of the first of 

 these countries and Jamaica, also appear to be of the wood- 

 pecker connexion. If we might judge by the structure of 

 the tongue, we should place the Humming Birds of America 

 in the same branch of the corvine genealogy: they eat 

 insects, although certainly more peculiarly fitted to draw an 



