x INVERTEBRATA OF MASSACHUSETTS. 



and for ascertaining also what shells are common to the two At- 

 lantic shores, I opened a correspondence, for information and 

 exchanges, with several distinguished European conchologists, 

 among whom I may mention Mr. G. B. Sowerby, of London, 

 and Dr. Loven, of Stockholm. The former is well known as 

 one of the most distinguished conchologists now living. To him 

 I sent every doubtful species, and such as I apprehended might 

 be identical with European species. Upon these he remarked at 

 length, and, whenever the species proved to be European also, 

 sent me European specimens for comparison, as well as such 

 other species as I had a particular desire to see. For the very 

 obliging and courteous manner in which he has thus assisted me 

 in solving my numerous doubts, I cannot express my obligations 

 too fully. 



With Dr. Loven, who has for many years been exploring the 

 seas of the north of Europe, and has examined the standard cabi- 

 nets of England, France, and Sweden, I have also exchanged 

 specimens. Hence I have obtained additional evidence of the 

 identity of many of the species inhabiting the American and Euro- 

 pean shores of the Northern Atlantic. 



I have pursued the same course with American conchologists, 

 in order to ascertain with certainty whether the shells of this State 

 are identical with those described by authors as found in other 

 and even very distant regions. I may here acknowledge my ob- 

 ligations in this respect to Dr. J. W. Mighels, of Portland, Prof. 

 Adams, of Middlebury College, Prof. Benedict, of Vermont 

 University, Dr. J. C. Jay, of New York, Mr. T. A. Conrad, of 

 Philadelphia, Mr. S. S. Haldeman, of Marietta, Pa., Dr. E. 

 Foreman, of Baltimore, Mr. J. G. Anthony, of Cincinnati, and 

 the late Dr. Ward, of Roscoe, Ohio. 



Wishing for every possible confirmation that the names I had 

 used were applied to the same shells that Mr. Say applied them 

 to, I visited the cabinet of the Academy of Natural Sciences, at 

 Philadelphia, where authentic specimens of most of the species 

 described by Mr. Say are deposited, and which is, in other re- 

 spects, a most valuable cabinet to the American naturalist, as it is 

 the most ancient. 



