Soul 
Arranged according to the number of Illinois species in each, 
these districts succeed each other in the following order. 
Per cent. of 
Districts No. of | ‘all Ilinois 
species species 
Lower Mississippi and Ohio valleys................. 134 89 
Upper Mississippi and Missouri valleys............... il) 87 
sibhtea Greate luallceumaGitin spas tes ahacer ok hale eos Oiswsnoteecue on 108 72 
sahereastyGlinGaStrich . cats csvs eter eee ea aes a emer 56 37 
Quebec and New England.. Sash hae og 53 36 
The west Gulf and Rio Grande ‘district. BR do Bootes MAES 47 31 
iexsOuUtLheAtlantiCrGiStrct. cs sivecucistee sais oe fees 45 30 
Tine inert Avilenalin@ GHGs s, 646 daccn soba ge aesscn ool 40 | Di 
A inys Team INf@yadlavgia eas aici cle Coa ae Ue Cle oa cee ee aie 37 25 
EeiepMlondaspeninculan iis tiiets sce s . Giee sere eee 23 | 15 
senesivucsonvd raimagcey ak akas 2 seks Sis cick clei toen ete Sars 19 13 
Mbire sealer io ttlawies traps ews oman us ka cae areata chs oe ay eh edesses 4. 3 
Next to the two Mississippi Valley districts and the Great Lake 
basin, which average 124 Illinois species, our fishes are most largely 
represented in the east Gulf and the Quebec and New England dis- 
tricts, averaging 54 Illinois species—the first closely related to the 
lower Mississippi, and the second a continuation eastward of the 
Great Lake basin. Then follow the north and south Atlantic and 
the west Gulf districts, with an average of 43 species; the far North, 
the Florida peninsula, and the Hudson River districts, with 37 to 19 
species; and, finally, the far Northwest, with but 4 Illinois species. 
The northern and the southern affiliations of the assemblage of 
fishes represented in our Illinois collections may be contrasted by 
comparing the list of Illinois species occurring in either or both of the 
more northerly divisions—that is, the far North and the Quebec and 
New England districts—on the one hand, with a list of those 
found in either or all of the three most southerly districts—that 1s, 
the Florida peninsula, the east Gulf, and the west Gulf and Rio 
Grande—on the other hand. In this northern list of Illinois fishes 
there are 64 species, and in the southern list there are 77; but 25 of 
these species are more or less common to both north and south, 
leaving 39 Illinois fishes distinctively northern in their distribution 
and 52 distinctively southern. Northern and southern species thus 
mingle in our territory in unequal proportions, the southern element 
largely preponderating. 
