118 PAPERS ON ZOOLOGY OF MICHIGAN. 



muck on the bottom. These were Sjyhaerium rhomboideum Say. -They 

 were taken in other parts of the marsh lakes, l3ut nowhere were they 

 found in such numbers as they were at Station 55. Sphaerium simile 

 Say, was found in a collection from the marsh "lakes. Three univalve 

 mollusks, Physa heterostropha Say, Planorbis antrosus striatus Baker, 

 and Physa gyrina Say, were incidentally collected with fish. Physa 

 gyrina was found only in the Shelldrake River, and the others in marsh 

 lakes and beach ponds west of Vermilion. 



The margins of the shallow marsh lakes are favorable places for 

 leeches. These creatures are ravenous, and much difficulty is ex- 

 perienced in keeping them from one's body while wading. The following 

 leeches were taken by the writer in the region: Placohdella rugosa 

 (Verrill), Haemopsis marmoratus (Say), Macrobdella decora (Say) Verrill, 

 Glossiphonia complanaia (Linn.) Johnston, Erohdella punctata (Leidy), 

 and Dina fervida (Verrill). 



Sponges, bright green in color, often formed extensive growths on 

 submerged brush, roots, logs, and other objects. The following were 

 collected: 



SpongiUa lacustris (Linn.), SpongUla fragilis Leidy, and Myenia 

 fluviatilis astrosperma Potts. 



These three forms appeared to be closely associated. 



Near the surface of one of the beach ponds, the water was a bright 

 green due to an abundance of ciliated protozoans {Stentor igneus Ehr.). 

 Another conspicuous protozoan in one of the marsh lakes produced 

 large, jelly-like colonies It appeared to be Ophrydium sp., which the 

 writer has found abundant in Walnut Lake, Oakland County, Michigan 

 (Hankinson, 1908). 



Vertebrates Other Than Fish. 



The amphibians and reptiles of the Whitefish Point region have 

 been studied and a paper published on them (Thompson and Thompson, 

 1913). A number of species were taken in the course of the field work 

 on fish, which were, Rana jjipiens Shr., Rana septentrional is Baird, 

 Ra7ia clamitans Latreille, Biifo americanus LeConte, Tharnnophis sirtalis 

 (Linn.), and Chrysemys belli Gray. Tadpoles were found in some num- 

 bers in quiet sunny shoals of Shelldrake River and Shelldrake Lake and 

 in shallow, quiet tributaries of Vermilion Creek. 



Many birds were present in the region during the time of the field 

 work, but like other terrestrial animals, they were given little attention. 

 A detailed report on the birds and mammals of the region has been 

 published by N. A. Wood (Annual Report of the Michigan Academy of 

 Science, Vol. XVI, pages 55-73). Since these forms have been treated 

 by Mr. Wood, only notes on the beaver, Castor canadensis michiga- 



