C2 



MM. CHICAGO ACADEMY OF SCIENCES. 



Species 



danielsi 



proxima 



p. rowelli 



leai 



tryonii 



traskii 



vahlii 



v. arctica 



v. pingelii 



neopalustris 



pallida 



catascopium . . . . 

 c. niagarensis. .. . 



■c. adamsi 



davisi 



pseudopinguis . . . 



nasoni 



woodruff! 



decollata 



sumassi 



jacksonensis . . . . 



gabbi 



emarginata 



e. mighelsi 



e. angulata 



■e. wisconsinensis . 



e. canadensis 



e. ontariensis. . . . 



contracta 



pilsbryana 



monlana 



oronensis 



binneyi 



apicina 



a. solida 



hinkleyi 



preblei 



randolphi 



alaskensis 



petersi 



atkaensis 



Total 



r.ii 



11 



■z 



c 



a 1 a a = 



i . u a 



~ " * ■ 7 



o - 



C 



= E 



: 1 % 



X - H 



J M « 



■ - 00 



K C « 



-- > 



- 

 - = 



A3 



B 



5i 221 16 9 19 9 36 



4 24 3 



1 



The above total reveals certain interesting facts. The Canadian 

 region is the best represented, containing 50 species and varieties, or 

 nearly one-half of the total fauna. The Upper Mississippian region 

 is next in representation, 36 species and varieties being known. The 

 Columbian (22), the Nova Scotian (24), the Californian (19) and 

 the Hudsonian (16) regions also contain a high percentage of species. 

 The poorly populated areas are the Carolinian (4), Central American 

 (3), West Indian (3), Greenlandian (3) and the Labradorian (1) 

 regions. Only three species are common to America and Asia. 



The country surrounding the Great Lakes is at present the center, 

 of distribution of this family, 55 species and varieties living in this 

 area, or more than half of the known species. Several species are 



