THE NAUTILUS. 7 



lime. Yet they still represent only a small part of the country, and 

 diligent, careful collecting in many more places and sections is badly 

 needed. 



That among such materials there should be many new forms was 

 to be anticipated, but the results were beyond all expectations. This 

 is partly proved by the many species already published. It seems 

 to be necessary to add that the greatest care has been taken in estab- 

 lishing r.ew species. All of them have been seen in every stage of 

 growth ; most are represented by hundreds and thousands of speci- 

 mens, and, in fact, the geographical range of almost all is a wide 

 one. And numerous new forms are in hand, partly have been 

 for years, awaiting new materials for their confirmation. Not only 

 the species in themselves are of interest and value, but also the study 

 of their geographical distribution and their variations. Some of the 

 Pisidia are extremely variable, and the same can be said of some of 

 our Sphaeria and Calyculimu, and their study is very difficult. 



This is not the place for an account of the work done by all con- 

 tributors, a summary of which will be given in a revision to be pub- 

 lished. Yet two conchologists have done such work and their suc- 

 cess is so unparalleled, the example given by them so suggestive and 

 encouraging, that we can not pass them over in silence. 



Mr. Olaf O. Nylander has, since '95, worked up Aroostook Co., 

 Me., and, beside other inollusca, collected and sent for examination 

 about 32,000 recent specimens and large numbers of fossil Pisidia. 

 His careful collecting, under great difficulties, in many places over 

 an extensive area of that northeastern part of our country, has added 

 very materially to our knowledge of the molluscan fauna. 1 



During the hist four years also, Dr. R. J. Kirkland, of Grand 

 Rapids, Mich., has collected and sent for examination about 123,000 

 Pisidia (over 70,000 in '99), and many thousand SpLseria and 

 Pisidia, most from Kent and some other counties of Michigan. And 

 it is of importance that both these enthusiastic collectors, like some 

 others also, have paid special attention to even the smallest speci- 

 mens. Thus we became acquainted with some minute species, while 

 the study of the young of all was greatly facilitated. On the other 

 hand, it. is very desirable, or rather indispensable, to have as large 

 numbers of specimens as possible at disposition, from every locality. 



1 See Mr. Nylander's list in THE NAUTILUS XIIF, p. 1<)2. (Jan., 1900.) 



