PLATE I 

Nt Ap 
` 
NS A AN A 
Wn S. WSS 
SYS. 




BURROWING ECHINI. 
photograph of a part of the side of the grotto in 
he photograph was kindly taken for me by Professor 
Northop of the School of Mines, New York City, to whom I am indebted for this and 
other kindnesses.—(See page zo.) 

