ERRATA AND ADDENDA. 



Page 55. line 15. for 185^ read 1855. 



Page 55. line 16, for Horticultural read State Agricultural. 



Page 60, in second table, Illinois, for S40 read S4I ■ 



Page 65, first line above foot-note, for vcntricosa read ligamcntina. 



Page 72, line 9, for imbccilis read inibccillis. 



Page 7Q, line 19, for asperimus read aspcrrimus. 



Page SO, above Quadrula rubiginosa insert Section Fusconaia Simpson. 



Page 76. The record of Calkins for Margaritana niargaritifcra is without 

 doubt erroneous and should be eliminated. This .species is not found in Illinois. 



Page 95. Pomatiopsis sheldonii Pilsbry should read Amnicola shcldonii and 

 should be transferred to the genus Amnicola on page 93. 



Page 100. Physa gyrina olcacca Tryon is the immature stage of Physa gyrina. 



Page 103. Lymncca tazewclliana is a synonym of Lymnira parva. 



Page 105. Lymncra pahistris michigancnsis is the immature fonn of Lynuuva 

 reflcxa. 



Page 106. Lytniura reflcxa ioivoLsis and Lymna'a reflexa crystalensis are 

 synonyms of Lymncca reflcxa. 



Page 112. line 6 from bottom, for gouldi read gonldii. 



Page 114. line 5 from bottom, iov juxtigens read juxtidens. 



Page 115, line 2 1 . for Witter read Walker; line 23 , Polygyra sayii Binney should 

 be changed to Polygyra sayaiia Pilsbry. 



Page 116, line 1. Polygyra exolcta Binney (1885) should be changed to 

 Polygyra zaleta Binney (1837). 



Page 117, line 11 from bottom, for leai read leaii; line 3 from bottom. Poly- 

 gyra monodon fratcrna is a good species and should read Polygyra fratcrna. 



Page 119, foot-note. A specimen of alliarius in the collection of Mr. Aldrich, 

 received from Calkins, proves to be draparnaldi. 



Page 121, line 3 from bottom, for Champaign read Piatt. 



Page 122, line 12 from bottom, for Pyramidula striatclla Anthony read Pyra- 

 midula cronkkitei antbonyi Pilsbry; line 4, for Held read Hald. 



Page 123, for Helicodiscus lineatus Say read Helicodiscus parallclns Say. 



Page 162, line 7, ior glandulosa read linearis. 



Page 171, line 17, for riparia read vulpina. 



Page 176, line 8 from bottom, for canadensc read majus. 



Page 180, line 9, for virginica read virginiana. 



Page 221, line 6 from bottom, for rcctaiigulus read rectangularis. 



Page 226, line 3, ior fasciatus read fasciata. 



Page 239, line 11, strike out Lake Co. entry. 



Page 246, lines 6 and 7, and page 248, lines 1. 14, 20, and 23, for (Jiiwthcra 

 read Onagra. 



Page 248, line 4, lor Candida Horn substitute n. sp. 



