136 KANSAS UNIVERSITY. SCIENCE BULLETIN. 



DISTRIBUTION BY RIVER SYSTEMS. 



In the following table the distribution of the different species 

 by river systems is shown. The arrangement I have adopted 

 is a simple one, the rivers emptying into the sea being arranged 

 in order, from those of Hudson Bay to the Gulf of Mexico. 

 Under each of these rivers, the tributaries are arranged in order 

 from the mouth towards the source, and the tributaries of these 

 are arranged in the same way. The names of streams flowing 

 into the sea are printed in capitals ; tributaries of the first, sec- 

 ond and third order in small capitals, italics, and lower case, re- 

 spectively. In some cases subdivisions have been made for 

 large bays. In the case of the St. Lawrence river system, sep- 

 arate parts, as the Great Lakes and the Niagara river, have 

 been most conveniently treated as separate tributaries of the 

 St. Lawrence river as the term is generally understood. 



Under the different streams are given alphabetical lists of the 

 species reported from them, with references to the number of the 

 state and the number of the locality in the state which is re- 

 ferred to this water system; C. carolinus, 41, 1, refers to "1. 

 Clinch R., Cumberland Gap, Claiborne county. (F.,'85)." In 

 assigning certain localities to a drainage system, considerable 

 difficulty has been experienced, especially in swampy regions, 

 as northern Indiana and the most of Florida, but I feel confi- 

 dent that the most of the localities are correctly assigned. In 

 many cases it has not been possible to determine from the lo- 

 calities given to what stream a species really belongs, and in 

 the table it has been placed under both possible systems, the 

 reference to the catalogue number followed by a question mark 

 in parentheses, C.bartonii,2,d,2 (?) , under both Raritan and Dela- 

 ware rivers. The intention of this table is to place each local- 

 ity in its proper drainage system. The species which are given 

 under Atlantic ocean and Gulf of Mexico are from localities 

 which could not well be assigned to any river, and probably all 

 the localities are drained immediately into the ocean or swampy 

 coast region. 



The arrangement is in the main an artificial one, but it pos- 

 sesses certain advantages, and seems the best, all things consid- 



