PREFACE. ■V 



group differs very materially from those of the first tbrcc, both 

 in size and in shape. The species of this fourth group have 

 hitherto been referred to the type species, the S2ih. hahiense, or 

 described as species of Pisidium ; they are very widely and 

 abundantly distributed through Central and South America and 

 the West Indies, where they take the place of the species of the 

 three first groups, none of which are found in those regions ; one 

 species inhabits South Africa. It is very desirable that the soft 

 parts of the species of this group should be submitted to exami- 

 nation, and I beg to recommend myself to the good offices of 

 naturalists collecting in the southern portion of this continent. 



I take this opportunity to acknowledge my indebtedness to 

 our late Mr. Cuming, of London, for his unprecedented liberality 

 in allowing all the specimens of Corhiculadse of his cabinet to 

 cross the ocean for my inspection, affording me thereby the only 

 possible means of identifying many of the species described in 

 Europe from this country. My thanks are also due to Mon- 

 sieur Deshayes, of Paris, for specimens of many of the species 

 of Corhiculadse from the Paris basin, by means of which I was 

 enabled to compare the American species with the fossil ones 

 of Europe. I am further under obligations to Mr. Hanley, of 

 London, for having determined for me a species described by him 

 from Central America ; to Mi\ Edward S. Morse for the able and 

 faithful manner with which he has executed the drawings on wood 

 inserted in the text of the monograph ; to my correspondents 

 abroad for the material which they have furnished me for insti- 

 tuting comparisons, and to my American correspondents for the 

 assistance they have afforded me in determining the geographical 

 range of the Corhiculadse of America, by sending me specimens 

 from all parts of the country. 



It is scarcely necessary to add that I have had the full use of 

 all the specimens of the Smithsonian Institution. 



TEMPLE PRIME. 



Huntington, L. I., N. Y., 

 December, 18(35. 



