158 KANSAS UNIVERSITY SCIENCE BULLETIN, 



habits. C. affinis has been shown to occur in very different 

 habitats. C. hlandingii is by no means confined to one type of 

 locality. The species given are sufficient to illustrate the point 

 in question. 



The distribution of the fresh-water fishes has been quite care- 

 fully worked up, and they have been in a limited way divided 

 into classes according to the character of the habitat.-* At the 

 present time it is not advisable to attempt to assign the cray- 

 fishes to groups in any but a provisional manner, but the avail- 

 able data for any species may be obtained from the tables of 

 distribution and the catalogue. Certain species it is possible to 

 limit quite definitely to some type of locality. 



Of species occurring in salt water only one is known : C. uhleri 

 is found in salt marshes and also in brackish and fresh water, 

 where C. hlandingii is sometimes found associated with it. Ac- 

 cording to Faxon ('85), Lake Tezcoco, where C. montezumse is 

 found, is said to be salt. 



The burrowing species obviously have a great advantage over 

 the other forms in distribution, in that they are able to occupy 

 territory which is not available for others except at certain 

 seasons. I may here call attention to their great range of dis- 

 tribution. C. diogenes is the most widely distributed species of the 

 genus, occurring in Boulder county, Colorado, at the foot of the 

 Rocky Mountains and southeastern Wyoming on the west, in 

 Minnesota, Wisconsin and Michigan on the north, in New Jer- 

 sey, Maryland, Virginia, North and South Carolina on the 

 east, and in Mississippi and southern Louisiana on the south. 

 C. argillicolais found in Canada on Lake Ontario, in Michigan, 

 Ohio, Illinois, Indiana, North Carolina, Mississippi, Louisiana, 

 and Texas. C. carolinus, long known from only the Appa- 

 lachian region of Virginia, is now known to occur in north- 

 eastern Indian Territory and western Pennsylvania. In how 

 far this distribution is to be explained by the habits of the ani- 



24. Jordan ( Science Sketches ) recognizes the following classes of fresh-water fishes : 



1. Lowland fishes. 5. Lake fishes. 



2. Channel fishes. 6. Anadroinous fishes. 



3. Upland fishes. 7. Catadromous fishes. 



4. Mountain fishes. 8. Brackish-water fishes. 



With the sixth and seventh we have nothing to do in the crayfishes. The fifth group is 

 hardly represented, or at least there are as yet very little data to indicate reasons for such a 

 group as Jordan has defined it. Several species have been reported from lakes, but whether 

 from the lake itself or from small tributaries or bays is not known in many cases. C stpfjius 

 is reported as washed up on the shores of Lake Michigan during a storm. With the first four 

 and the eighth group we may be concerned, but it is impossible at the present time to give a 

 list assigning more than a few of the species to a definite type of locality. 



