Note. 649 



ated surfaces, and is structureless. It appears to be connected 

 with the upper and the lower membranes at the front, and at the 

 two lateral margins of the scale, but not at the posterior extremity, 

 to which it does not fully extend, stopping short of that margin by 

 a considerable interval. Its function seems to be to stiffen and to 

 support the two perforated membranes, which are so exceedingly 

 delicate, and so susceptible to injury, that the process of mounting 

 them in balsam has in many instances stripped them from the 

 structureless basement membrane, leaving it bare and conspicuous, 

 with only a few perforated fragments scattered over its surface. 



Trenton, New Jersey, U.S.A. 



