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what larger than those found at the other lakes. No young were found, 

 the smallest shell obtained being a half-grown example. One gravid 

 specimen was found at Lost Lake September 7, 1908. The marsupium 

 closely resembles that of L. iris, being a kidney shaped mass filling the 

 hinder portion of the outer gill, this mass marked into segments by 

 rather deep radiating furrows. The very edge of the marsupium is 

 white, beyond the dusky submarginal area, the white making a chain- 

 like area at the edge of the gill. Like L. iris, this species has a tendency 

 to form pearls, but they are too small to be of any value. 



Food of individuals: The following is the result of the examina- 

 tion of the contents of the intestines of L. subrostrata from Lost Lake 

 at vai'ious dates. 



Sample 22. August 20, 1908. A small amount of flocculent bluish- 

 gray material. Peridinium tabulatum, abundant; Microcystis serugi- 

 nosa, abundant; Anunea cochlearis; Pediastrum boryanum; Diatoms — 

 Synedra; Cocconema cymbiforme. 



Sample 23. August 20, 1908. A very small amount of flocculent 

 grayish material. Peridinium tabulatum, a few; Microcystis aeruginosa, 

 a little; Pediastrum boryanum; CosmaHum; Tetraedron minimum; 

 Scenedesmus ; Euglyphia alveolata; Peridinium, a small, sharp-spined 

 form. Diatoms make up the greater part, including Cocconema cymbi- 

 forme; Navicula; Fragiluria; Coscinodiscus ; and Epithemia. 



Sample 24. September 7. A large amount of material, black mud 

 below, greenish flocculent material above. The upper portion contains 

 chiefly Botryococcus braunii and Microcystis aeruginosa. Bottom por- 

 tion — Microcystis aeruginosa, common; Botryococcus braunii; Peridinium 

 tabulatum; Peridinium, a small-spined species; Scenedesmus, frequent; 

 Staurastrum; Pediastrum duplex; Ccelastrum, a few; Anurasa coch- 

 learis; Tetraedron; Docidium; Ccelosphaerium kuetzingianum; Sponge 

 spicule; Lyngbya aestuarii; Diatoms, Synedra; Navicula; Goviphonema; 

 etc. 



10. Lampsilis luteola (Lamarck). Fat Mucket. 



Lampsilis luteola is the most widely distributed of the American 

 Unionidae, its range extending over nearly all of North America east 

 of the Rocky Mountains. It lives and thrives under a great variety of 

 conditions, being frequent in both lakes and rivers. 



