208 ANIMAL INTELLIGENCE. 



struction of its cells), but also ramifies into a number of 

 diverse directions. Thus we have, in different species, 

 wide open networks spread between the branches of bushes, 

 &c., closely woven textures in the comers of buildings, 

 earth tubes lined with silk, the strong muslin-like snare 

 of the Mygale, which, as first noticed by Madame Merian,^ 

 and since confirmed by Bates,^ is able to retain a struggling 

 humming-bird while this most beautiful animal in creation 

 is being devoured by the most repulsive ; and many other 

 varieties might be mentioned. It may at first sight ap- 

 pear somewhat remarkable that this instinct of spreading 

 snares should on the one hand occur only in one class of 

 the animal kingdom, while on the other hand, in the class 

 where it does occur, it should attain such extreme perfec- 

 tion, and run into so much variety. But we must here 

 remember that the development of the instinct obviously 

 depends upon the presence of a web-secreting apparatus, 

 which is a comparatively rare anatomical feature. In 

 caterpillars, which are not predaceous, the web is used only 

 for the purposes of protection and locomotion ; and it is 

 easy to see that the spreading of snares would here be of 

 no use to the animals. But in spiders, of course, the case 

 is otherwise. Once granting the power of forming a web, 

 and it is evident that there is much potential service to 

 which this power may be put with reference to the vora- 

 cious habits of the animal ; and therefore it is not to be 

 wondered that both the anatomical structures and their 

 correlated instincts should attain to extreme perfection in 

 sundry lines of development. The origin of the web- 

 building structure was probably due to the use of the 

 web for purposes of locomotion or of cocoon-spinning, as 

 we see it still so used in the same way that it is used by 

 caterpillars for descending from heights, and in the case 

 of the gossamer spider for travelling immense distances 

 through the air. As the anatomical structures in question 

 differ very greatly in the case of spiders and in that of 

 caterpillars, we may wonder why analogous if not homolo- 



' Natwralist on the Amazon, p. 83. 



2 For many other confirmations see SirE. Tennent, Nat. Hist.Ceylony 

 pp. 468-69. 



