FISHES OF DOUGLAS LAKE, MICHIGAN. 239 



2 feet deep. The eggs were laid in the sand and were fed upon by the log perch them- 

 selves as well as by suckers. A preliminary note on the breeding habits has been 

 published (Reighard, 191 3). A detailed account will be published later. 



BoLEOSOMA NIGRUM (Rafinesque), johnny darter, is common in Douglas Lake. Its 

 distribution in the lake and the factors controlling it are the subjects of a paper by Mr. 

 H. V. Heimburger, now in manuscript (see also Heimburger, 191 3), from which the 

 following, statements are extracted : 



It occurs commonly in water of about 18 inches depth, on bottom which contains 

 some muck and in the neighborhood of aquatic plants. The food of the adult consists, 

 in midsummer, chiefly of larv^ae of midges, but partly of Entomostraca. The midges 

 lay their eggs on the floating leaves of aquatic plants and their lar\^ae are found in muck 

 near by. It is well known that the eggs of this species are laid under stones, sticks, 

 mussel shells, and the like in shallow water and are guarded by the male fish. Mr. 

 Heimburger concludes that the localities in which the johnny darter occurs in Douglas 

 Lake present "several features in common: (i) Mussel shells, sticks or stones are found 

 on the bottom; (2) quiet water protected from prevailing winds so that the bottom is 

 not subject to violent wave action; (3) a thin deposit of muck in the shallows, with 

 patches of clear sand exposed ; deeper muck deposit is found in the deeper water of the 

 locahty, but a deep muck deposit is not found in the shallow water; (4) masses of Pota- 

 mogeton, etc., are found near the habitats where both adults and young are found. 

 These factors are seen to be related very definitely to the food or breeding habits of 

 Boleosoma and may therefore be regarded as factors determining the local distribution 

 of this species." 



Etheostoma 10W.E Jordan and Meek is rare in Douglas Lake. Two specimens 

 were taken in the minnow seine along with 75 johnny darters at the west side of the 

 entrance to North Fishtail Bay in September, 191 1. One was taken on sand bottom 

 at the mouth of Bessie Creek. The species is recorded by Hankinson (1908) from 

 Walnut Lake. The two Michigan records appear to mark the eastern limit of its range, 

 which is the Mississippi Valley and northward. 



CoTTUS ICTALOPS (Rafinesque), miller's thumb. — This species is rare in Douglas 

 Lake, and our records indicate that it is confined to the stony shoals. Its eggs are known 

 to be laid under stones and other objects lying on the bottom and to be guarded by the 

 male fish. We have found it in the lake only in localities which afford it nesting sites. 

 These are Grapevine Point and the west side of North Fishtail Bay. In the latter local- 

 ity it is recorded as abundant under stones. We have taken it also in Maple River. 



Lota maculosa (Le Sueur), burbot. — We have taken a young individual about 2^4 

 inches long at the mouth of Carp Creek, where it enters Burts Lake. It was taken with 

 Umbra limi, near dense masses of aquatic vegetation. Prof. N. H. Stewart is reported 

 to have taken two very large specimens in a gill net in Douglas Lake in the summer of 

 1910. 



nSH COMMUNITIES OF DOUGLAS LAKE. 



In the second part of this paper there is suggested a classification of the fish habitats 

 of the lake. The fish found within each of these habitats in midsummer might now be 

 considered without reference to other habitats. But since fish may pass from one 

 habitat to another with increase of size and change of food, it seems best to consider 



