304 Transactions. — Zoology. 



part of the lid on the under side is protuberant, as shown in fig. 7, at the 

 part that is unhinged, and it is there tlie hd is thickest. There is, too, an 

 indent into the side of the hp of the nest opposite this protuberance on the 

 hd, and into which it fits as shown in fig. 8 (which represents mouth of 

 nest with the door off) causing the lid, when shut down, to lock, as it were, 

 like a dove-tail, so that in order to open it again you have to insert a knife 

 between the trap-door and the mouth of the nest. This trap-door with its 

 hinges, locking apparatus, and counter-sinking is, I think, one of the most 

 marvellous mechanical arrangements that I have ever come across in 

 nature. No one can attentively examine this ingenious contrivance without 

 being impressed with the fact that here in one of what we are accustomed 

 to call the lowest class of animals, we have something wondi'ously akin to 

 the inventive faculty in man. But this paper is one of facts and not specu- 

 lations, and so I must forbear. As in the previous instance there is no 

 sj)ring in the hinges, so that the trap-door remains open when left open. 

 Though the outside appearance of the trap-door represents the segment of 

 an oval, still the contour of the hole inside below the coimter- sinking is 

 nearly circular as shown in fig. 8. 



Nos. 3 and 4. — The other two Californian nests are in the same character 

 of ground as the preceding, and are of the same shape, and have the same 

 description of hinge as No. 1, only they are both of smaller size. They are 

 both thickened on the under side and bevelled on the edges like the others. 

 No. 3 though hinged across has a protuberance slightly developed on the 

 under side of the lid in the centre of the hinge area the same as No. 2, 

 suggesting the idea that possibly the two hinges in that nest may have been 

 caused by the locking effect of the protuberance as it is increased in size, 

 but there is no evidence of unfinished or wraggied edges in No. 2 indicative 

 of the separation having been effected by such a wearing process. On the 

 under side of the hd of No. 4 on the free edge there are two distinct holes 

 or claw marks exactly in front, but they do not penetrate through the lid. 

 Both nests are lined with very tough web, are tortuous, but have no 

 enlargement. 



Nests from Western Australia. 



These two nests (which were presented by His Excellency Governor 

 Weld) differ entirely from the Californian, They are raised above the surface 

 of the ground, and the hd fits on to the mouth of the nest like a cap, 

 overlaps somewhat all round, and is thickened entirely on the outside. 

 They are also smaller in size than the Cahfornian. 



Nest No. 1 is almost circular (fig. 9: a trap-door closed; b small nest 

 without lid) ; across the mouth outside it measures six-tenths of an inch, 

 whilst the lid fitting over it measures seven-tenths ; across the mouth insidq 



