MONOGRAPH OF THE UNIONID^ OF N. AMERICA. 141 



Dexter, Iowa, that they have in course of preparation a " Mono- 

 graph of the Unionids of North America." The want of such 

 a work has been long felt, and we sincerely trust our brother 

 Conchologists of America will, with their characteristic ardour 

 and readiness, give that hearty co-operation in providing the 

 necessary material, &c., for the effective carrying out of the un- 

 dertaking. The prospectus, a copy of which we have been 

 favored with, says : — 



" All aid will be acknowledged in due form ; and, to parties 

 desiring it, liberal exchanges will be given. It is designed to 

 figure the anatomy of every species in detail, and to this end 

 shells with their animals should be carefully preserved in alcohol 

 —from three to five specimens of each species — -and a careful 

 record of date of capture and locality kept. 



" Your special attention is called to the physical geography 

 of the area included within the field of your operations, and to 

 the fact that the value of your collections will- be increased by 

 the inclusion of a great variety of stations. By the comparison 

 of the results of such careful examinations it is hoped that an 

 accurate knowledge of the distribution of the Unionidiz may be 

 obtained, together withjhe effect of environment on their habits, 

 growth and economy. Such observations, it is notorious, have 

 been either loosely or not at all recorded. Your co-operation is 

 respectfully requested in the preparation of local lists, where you 

 have not the specimens to spare, Avhich shall include a record of 

 the name of stream, nature of bottom, force of current, nature 

 of the water, add associated species of univalves. Aberrant and 

 peculiar forms are especially desired. 



" On small parcels, to be sent by mail, postage will be 

 remitted on notification of the amount. Boxes and heavy parcels 

 may be sent by express at the expense of the consignee. It is 

 unnecessary to add that the completeness and value of the pro- 

 posed work will depend largely upon the response made by the 

 conchologists of America, which, it is hoped, will be liberal. A 

 large mass of interesting and valuable notes must exist in the 

 hands of those who study these forms, which, if sent to us, will 

 find a place in the Monograph, carefully attributed to their re- 

 spective observers." 



