518 APPENDIX. 



22. Unio ebenus, Lea. Upper Mississippi, between Prairie du 

 Chi en and Lake Pepin. 



23. Unio gibbosus, Barnes. St. Croix Eiver, Upper Missis- 

 sippi. 



24. Unio rectus, Lamarck. U. PR^LONGUS, Barnes. Upper 

 Mississippi, from Prairie du Chien to Lake Pepin, and the Eiver 

 St. Croix. The specimens collected by Mr. Schoolcraft, vary- 

 much in the color of the nacre. Some have it entirely white, 

 others rose purple, and others entirely of a very fine dark salmon 

 color. This species inhabits the St. Lawrence as far east as 

 Montreal. 



25. Unio siliquoideus, Barnes^ and U. INFLATUS, Barnes. 

 Upper Mississippi, between Prairie du Chien and Lake Pepin. 

 Large, ponderous, and the epidermis finely rayed. 



26. Unio complanatus, Lea. U. purpureus, Say. Lake 

 Vaseux, St. Mary's Eiver. Lake Yaseux is an expansion of the 

 Eiver St. Mary, a tributary of the upper lakes. This shell does 

 not appear to exist in any of the streams flowing into the Mis- 

 sissippi. 



27. Unio crassus, Say. Upper Mississippi, Prairie du Chien. 



28. Unio radiatus, Barnes. Lake Yaseux. The specimen is 

 old and imperfect, but I believe it to be the U. radiatus of our 

 conchologists, which is common in Lake Champlain and also in- 

 habits the St. Lawrence. 



29. Unio occidens, Lea. U. ventricosus, Say, Am. Con. U. 

 ventricosus, Barnes ? "Wisconsin and St. Croix Elvers, and Shell 

 Lake. Epidermis variously colored, and marked with numerous 

 rays. 



30. Unio ventricosus, Barnes. Upper Mississippi, from Prairie 

 du Chien to Lake Pepin and Shell Lake. The varieties of this, 

 and the preceding pass insensibly into each other. Those from 

 Shell Lake are of extraordinary size. 



31. Unio alatus. Say. Symphynota alata. Lea. Upper 

 Mississippi, and Shell Lake. Found also in Lake Champlain, by 

 the late Mr. Barnes. 



32. Unio gracilis, Barnes. Symphynota gracilis. Lea. 

 Upper Mississippi, and Shell Lake. The specimens brought by 

 Mr. Schoolcraft are larger and more beautiful than I have seen 

 from any other locality. 



