DR. THEODOK NEUMANN. 181 



tion between their structure and the electrical condition 

 of the atmosphere. The injurious effect of a sudden in- 

 crease of electricity is very strongly marked upon the 

 young of all animals, the hurtful influence being in pro- 

 portion to the growth of the victim. Eggs are peculiarly 

 susceptible to the influence of electricity, and are, even 

 when the embryo is i)artially matured, often killed by a 

 passing thunderstorm. In climates where thunderstorms 

 are frequent and violent, it is needful that the eggs should 

 be protected from the deadly influence, and we accord- 

 ingly find that the nests are oval or rounded in shape, 

 and made of substances which are bad conductors to 

 electricity. 



Of other birds whose structures must be classed among 

 those of this group let me name the pinc-pinc, the 

 copocier, and the schapu. The nest of the pinc-pinc 

 (Drymoica textrix) is of considerable dimensions, being 

 often more than a foot in circumference, and of a most 

 singular shape and structure. The materials of which it 

 is composed are vegetable fibres, beaten, twisted and 

 woven into a fine felt-like substance, and strongly fast- 

 ened to the branches among which it is situated. It is 

 of a rough, gourd-like shape, and always entered by 

 means of a neck or spout, so that the bird is able, 

 from the interior, to present its sharply pointed bill to 

 any assailant, and to prevent its entrance. Near the 

 mouth of the nest there are generally one or two pro- 

 jections, which serve as perches for the bird to rest upon 

 before it enters the nest, and may probably be used by 

 the male as a seat whereon to recline while his mate is 

 sitting upon the eggs within. The color of the nest 

 varies according to the substance of which it is com- 

 posed, sometimes being of a snowy whiteness, and at 

 other times of a dingy brown. 



Another species of the same genus, the copocier, builds 

 a nest which, although of coarser texture, is quite as 



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