134 PAPERS ON ZOOLOGY OF MICHIGAN. 



Marsh Areas. The water in the sedge marsh close to the lake is 

 frequented by mud minnows and a good many small examples of other 

 species common in the lakes. The latter was composed of black-head 

 minnows, brook sticklebacks, Iowa darters, Leuciscus neogaeus, and 

 silvery minnows. These were mostly about an inch in length and 

 were caught chiefly in the marsh near Station 55 and at Station 115. 

 When the marshes are artificially flooded, the small fish of the lakes 

 are said to go over them in large numbers. The marshes are undoubt- 

 edly used as breeding grounds for pike in the spring, and people living 

 at Vermilion tell of their coming into these places at that time. 



Some water insects and other invertebrates were taken in the marsh. 

 Mosquitoes were very numerous. A few specimens belonging to the 

 species, Anopheles quadrimaculatus, were caught. About the bases of 

 the sedge plants some dragon fly larvae (Plathemis lydia and Somata- 

 chlora) were taken, also a few snails {Planorbis anirosus striatus and 

 Physa heterostropha) . 



Beaver Channels and Pools in the Marsh. These are narrow passages 

 through the marsh dug by beavers. Some of them are quite deep and 

 extensive as at Station 51. These lead to houses, a number of which 

 are on the island in the east part of Beaver Lake. The passages are 

 from about two to seven feet in width and three or four feet deep, and 

 have a great deal of the soft muck on their bottoms. Five radiating 

 from the house and one connecting the channel system with the lake 

 are present at this station. Many small fish frequented them, but no 

 collections of them were made. To what extent beavers are a factor 

 in forming little bays like Station 52 and 55, is an interesting problem. 

 It can readily be seen how a group of radial channels like those of Sta- 

 tion 51 could start one of these bays by being widened till the marsh 

 between them is obliterated. 



Wooded Lake Border. Stations 85 and 110 are of this type. Trees 

 here prodiice much shade, which is the chief characteristic of this type 

 of habitat. Much submerged brush is present, which furnishes hiding 

 places for small fish. On the shore with trees are many shrubs, logs, 

 fallen limbs, and much herbage, including sedge growths. The lake 

 margin is cut up by little bays or channels that are numerous on the 

 swamp floor. The following species were caught along wooded shores: 

 black-head minnow, red-bellied dace, Leuciscus neogaeus, Cayuga 

 minnow, brook stickleback, and common pike. 



Pikes find many retreats in the shore indentations. Black-head 

 minnows were numerous at Station 85, and hundreds of them crowded 

 up into the little bays and channels. Brook sticklebacks also fre- 

 quented these places in some numbers. Attached to the submerged 



