872 Transactions of the American Institute. 



leaves. As the exhalation of oxvgen is greatest when sunlight falls 

 on the npper surface of leaves, Barthelemj explains this by suppos- 

 ing that the respiration takes place through the cuticle of the upper 

 sui-face, while the stoniata or pores of the under surface perhaps 

 absorb only nitrogen. 



IIeaeixg Organs of Crustacea. 

 Sir John Lubbock, in discoursing on Crustacea, says: We do not 

 understand how they see, smell, or hear; nor are entomologists 

 entirely agreed as to the function or the structure of the antennae. 

 This interesting subject offers a most ])romising field for study, and 

 I would particularly call the attention of entomologists to a remarka- 

 ble memoir by Hensen, on the auditory organ in the decapod 

 Crustacea. Hensen has shown that the otolithes in the open auditory 

 sacs of shrimps are foreign particles of sand, introduced into tlie organ 

 by the animal itself. He proves this very ingeniously by placing 

 a shrimp in filtered water, without any sand, but with crystals of 

 uric acid. Three hours after the animal had moulted, he found that 

 the sacs contained many of these crystals. M. Hensen has also 

 shown that each hair in the auditory sac is susceptible of being 

 thrown into vibration by a particular note, which is probably deter- 

 mined by the length and thickness of the hair. It may be experi- 

 mentally shown that certain sounds throw particular hairs into rapid 

 vibration, while those around them remain perfectly still. 



Endless Chain Saw. 



Mr. D. L. Kennedy exhibited his endless cliain saw. It U made 

 up of links or sections, each one complete in itself, and joined to its 

 fellows by a hook joint, having no lap or pivot. A number of these 

 complete the saw, which is carried by two grooved pulleys or wheels, 

 one of these having adjustable beartngs, so as to strain tlie saw to 

 any required tension. This saw claims to possess the good points 

 peculiar to both the straight line action of the reciprocating saw, 

 and the continuous movement of the circular saw. 



The inventor claims that the following are some of its leading 

 advantages. 



Ist. Its Unlimited Dimensions. — As it can easily be exteuded from 

 •cutting two feet timber to six feet timber, by raising tlie upper wheel, 

 and adding the requisite number of sections, the thickness of tlie saw 

 remaining the same. To do this with a circular saw would rc(piirc 



