61 
The principal deficiencies in our survey of the ichthyic fauna of 
he State are likely to be found in the small prairie sloughs of 
Northern Illinois, in the lower Rock River and its tributaries, 
especially the Green River basin), in the Kaskaskia River, and in 
he Mississippi, along the western border of the State. 
The previously published lists of the fishes of Illinois are but few. 
the first contribution to the subject was a very brief list of com- 
non species by Mr. Robert Kennicott, occurring in a catalogue of 
he animals of Cook county, published in the Transactions of the [lli- 
10is State Agricultural Society for 1:53-4 (Vol. I). In the bulletin 
vw the ILlinois Museum of Natural History, published by us 
n 1876, was printed a partial catalogue of the fishes of 
llinois, prepared by Mr. E. W. Nelson from the fishes at 
hat time in the State Laboratory of Natural History. The cir- 
tumstances under which this catalogue was. prepared, and the 
lumerous changes in nomenclature and in the definition of species 
nade since that day, render the list of little present authority, 
specially as inference and general information seem to have been 
jometimes depended on in making up the notes on distribution. A 
ecoud catalogue, published two years after in the second bulletin 
~ the Laboratory, prepared by Prof. David 8. Jordan with some 
issistance from the present writer, based, like the preceding, chiefly 
ypon the Laboratory collections, was more complete and authorita- 
ive; but the progress of ichthyology and a more careful study of 
he specimens since that date, together with more extensive collec- 
ions within the State, render this list also largely obsolete. 
In the preparation of the following, [.have been under especial obliga- 
ions to Dr. Jordan for notes respecting the synonomy, contributed in 
idvance of publieation, and also for a few facts of distribution. Ihave 
ollowed, in the main, the arrangement and nomenclature of the 
‘Synopsis of the Fishes of North America,” by Jordan and Gilbert, 
published as Bulletin No. 16 of the United States National Museum, 
mut have expressed my own views with regard to distinctions of 
fenera and species. The grounds for such changes in nomenclature 
i§ are here made, will be given in full in my report on the cold- 
jlooded vertebrates of Illinois, now nearly ready for the press. 
In order to afford a clear explanation to students of the sense in 
vhich I have used generic and specific terms, I have ‘referred to 
he above mentioned list in Bulletin No.2, of the State Laboratory 
% Natural History, (1878), and to Jordan and Gilberc’s Synopsis 
Bul. 16, U. S. Nat’l Mus.), in every case where I have departed 
rom the nomenclature or grouping of those papers, the references 
eing made to names with which those here used are to be taken 
i8 synonymous. For the first of the above references I have used 
he abbreviation “‘Bul. 2”; for the second, ‘‘Synop.”’ 
®The nomenclature of the second edition of Jordan’s ‘“‘Manual of 
he Vertebrates of the Eastern United States” is nearly the same 
i8 that of the list in our Bulletin 2, published the same year. 
Where it varies, I have added a citation to the ‘‘Manual,” using 
ihe abbreviation ‘““M. V.” 
