TO 
ALFRED lEWTOI, P.E.S, F.L.S,, F^.S, 
PEOFESSOE OF ZOOLOGY AND COMPAEATIVE ANATOMY IN THE UNIYEESITY OF CAMBEIDGE, &c., &c., &c., Ac. 
IN APPEECIATION 
OF AN 
UNINTEREUPTED FEIENDSHIP 
EXTENDING OVER A PERIOD OF MORE THAN THIRTY YEARS, 
THIS WOEK IS DEDICATED 
BY 
HIS SINCERE FRIEND AND ADMIRER, 
THE AUTHOR 
