238 The Nahtralist in La Plata. 



ing this family likeness in colour, any person, not 

 an ornithologist, looking at a collection of speci- 

 mens comprising many genera, would hear with 

 surprise and almost incredulity that theyall belonged 

 to one family, so great is the diversity exhibited in 

 their structure. In size they vary from species 

 smaller than the golden-crested wren to others 

 larger than the woodcock ; but the differences in 

 size are as nothing compared with those shown in 

 the form of the beak. Between the minute, straight, 

 conical, tit-like beaks of the Laptasthenura — a tit 

 in appearance and habits — and the extravagantly 

 long, sword-shaped bill of Nasica, or the excessively 

 attenuated, sickle-shaped organ in Xiphorynchus, 

 the divergence is amazing, compared with what is 

 found in other families ; while between these two 

 extremes there is a heterogeneous assemblage of 

 birds with beaks like creepers, nuthatches, finches, 

 tyrant-birds, woodpeckers, crows, and even curlews 

 and ibises. In legs, feet and tails, there are corre- 

 sponding differences. There are tails of all lengths 

 and all forms ; soft and stiff, square, acuminated, 

 broad and fan -like, narrow and spine-like, and 

 many as in the woodpeckers, and used as in that 

 bird to support the body in climbing. An extremely 

 curious modification is found inSittosoma : the tail- 

 feathers in this genus are long and graduated, and 

 the shafts, projecting beyond the webs at the ends, 

 curve downwards and form stiff hooks. Concern- 

 ing the habits of these birds, it has only been 

 reported that they climb on the trunks of trees: 

 probably they are able to run vertically up or down 

 with equal facility, and even to suspend themselves 



