The British Guiana Museum. 259 
sented, their places being taken by such families as the 
sugar-birds, the American creepers, the tyrant-shrikes, the 
bush-shrikes or ant-thrushes, the manakins, the cotingas 
or chatterers, the hang-nests or cassiques, and the 
tanagers, all of which are confined to America, and chiefly 
to the tropical regions. All these birds are charafterised by 
having rather thin but strong feet, adapted for perching, 
three toes dire6led forwards and one toe backwards, the toes 
beingusually longandthin,and with long and sharp, narrow 
claws. The charaflers on which the families and other 
groups are founded, are based on the shapes and sizes of the 
bills, the position and shape of the nostrils, the length 
size and freedom of the toes, the relative lengths of the 
quill feathers of the wings, etc., together with various 
internal charafters. 
Of the family of the thrushes, several specimens 
are shewn in the flat-case (1), not only of true thrushes 
(Turdus) of the colony, but also of the mocking-thrush 
(Mimus) to which group belongs the wonderful mocking- 
bird of North America. In these birds the bills are 
rather long, compressed, thin, and strong, and slightly 
vaulted and hooked at the tip. 
Of the family of the wrens, several dull-coloured 
specimens are shewn in the flat-case next to the 
thrushes. They are always small birds, and they have 
thin, long and nearly straight bills. They are common 
about houses in town, and their twittering is very musical, 
rising at times almost into song. The formidable name 
Troglodytes^ which the tiny common wren bears, has been 
given to it to describe its sele6lion of some secluded 
corner or hollow in which to make its nest, the better to 
hide it. 
