TREFACE. V 



the great expense of illustrations, I have been obliged to omit the 

 Bryozoa, and the Radiata, Crustacea, and other branches of Inver- 

 tebrata included in the first edition. 



Should any disappointment be felt that Dr. Gould has not adopted 

 in his work all the improvements in classification, &c., which more 

 recent investigations have suggested, it must be remembered that 

 this is not a new work. It is rather a reprint of an old one, with 

 such additions and improvements as Dr. Gould considered abso- 

 lutely necessary to its present usefulness. 



In closing my Preface I must refer to the peculiar pleasure I have 

 taken in being able, in some slight manner, to repay the encourage- 

 ment, assistance, and constant kindness of the author to myself, in 

 my conchological studies, and especially to return the similar ser- 

 vice which has already united the names of Gould and Binney in 

 authorship. 



W. G. B. 



