100 THE LIFE OF DEVILS LAKE 



The ability of frogs and salamanders to tolerate the highly 

 concentrated water of Devils Lake, is of great interest, in view of 

 the inability of most species of fish to live therein. Further con- 

 sideration of this question is given below.* 



AVES 



In his recent report on the birds of North Dakota Wood (1923) 

 lists 67 species of water birds at Devils Lake, divided among the 

 following orders : Colymbiformes, 6 ; Ciconiiformes, 5 ; Anseri- 

 formes, 23; Charadriiformes, 33. 



While birds are not, properly speaking, a part of the life of a 

 lake, they nevertheless play an important part in its bionomics by 

 feeding extensively on the insects and other organisms which it con- 

 tains. 



MAMMALS 

 The only mammal present in Devils Lake, other than accident- 

 ally, is the muskrat, (Fiber zibethicus cinamominus). This is 

 frequently seen swimming in the lake, and what are undoubtedly 

 its burrows may be found occasionally on the shore, but I have 

 never seen any of its "houses" in the lake. It is not numerous, 

 and plays a minor role in the biology of the lake. 



PARASITES 

 There are of course several parasites infecting various mem- 

 bers of the Devils Lake fauna, but no study has been made of them. 

 While, in a broad sense, they might be considered members of the 

 fauna, in a stricter sense, they are not, since their habitat is deter- 

 mined for them by their hosts, and is not, at least so far as known, 

 influenced by the physico-chemical environment of the water in 

 which the hosts may happen to live. 



DISCUSSION OF RESULTS 



Devils Lake is interesting as well for what it does not, as for 

 what it does contain. Derived from an originally fresh body of 

 water, it probably at one time contained representatives of all the 

 larger groups of fresh water animals. At present there are no mem- 

 bers of the sponges, celenterates, nemerteans, annelids, bryozoans, 

 molluscs or reptiles in the alkaline waters of the complex, altho 

 sponges, leeches and molluscs and turtles occur in some of the fresh 

 water ponds, which at one time were part of Devils Lake. Thus far 

 no hydroids, nemerteans or bryozoans have been found in any part 

 of the complex, either alkaline or fresh. Large numbers of snail 

 shells, including several species occur along the shores of Devils 

 Lake, but apparently no living species at present inhabit its waters. 

 At one point, in a gravel bed, many mussel shells occur, evidently re- 

 mains of a former fresh water fauna. 



♦See p. lOG. 



