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CASSELLS BOOK OF BIRDS. 



similar to that adopted by the Kusappi, but, as we have already said, it builds entirely with the 

 gelatinous threads, without any foreign admixture. We have frequently remarked that such of these 

 birds as are well fed exhibit a much more considerable enlargement of the glands than is observable 

 in those that have only been able to obtain a scanty supply of nourishment. This fact explains the 

 reason why so much difference is constantly noticeable both in the size and beauty of these much- 

 prized nests, millions of which are annually consumed, such as are very clear and delicate often 

 realising fabulous prices. Java is particularly rich in this article of commerce, and Epp thus describes 



THE WHITE-THROATED PRICKLY-TAILED SWIFT (Acantkylis CaudaCUla). 



one of the localities in which the nests are most numerously met with: — "The Karang Kallong," he 

 says, " is a huge chalk rock, rising perpendicularly from the sea, by which it is surrounded, and is 

 garrisoned with a force of twenty-five men, whose sole duty is to protect the birds while building. 

 A large tree grows at the edge of the steep, and from this point of view those who venture to look 

 down behold the busy workers swarming beneath, appearing in the distance no larger than bees. 

 The sides of the precipice contain nine caverns, each of which has its name, and can only be entered 

 by a man lowered from above ; should the rope break, his death is inevitable, and even if this 

 danger be escaped, the task of finding the entrance to the cavern is attended with great peril, as the 

 foaming waves constantly dash high enough to conceal it from view. The natives who engage in this 



