538 



THE CHICAGO ACADEMY OF SCIENCES. 



Planorbis, 29, 84, 121. 



albus, 54. 

 " arcticus, 54. 



bicarinatus, 322, 388. 

 " bicarinatus royalensis, 25. 



" binneyi, 20, 155. 



campanulatus, 25. 

 " carinatus, 41. 



corneus, 41. 

 marginatus, 41. 

 parvus, 247, 414. 

 rotundatus, 54. 

 spirorbis, 41. 

 trivolvis, 20, 29. 

 vortex, 41. 



Planorbidae, 121, 124. 

 planulata, 285, 286, 289. 

 platystoma, 463. 

 plebeia, 300, 305, 313. 

 Pleurolimnsea, 3, 93, 103, 123, 124, 



198. 



plica, 87, 282, 283, 285, 286, 289. 

 plicata, 285. 



Polygyra albolabris, 340. 

 thyroides, 340. 

 Polyrhytis, 3, 103, 123, 124, 127, 458, 



460. 



Pompholyx, 121, 122, 128. 

 praecellens, 465. 

 preblei, 445, 450-452. 

 proxima, 53, 337, 358-363, 367, 369. 



PSEUDOSUCCINEA, 126, l62. 



pseudopinguis, 366, 395, 396. 



pngio, 353, 466. 



Pupa vermilionensis, 80. 



" vetusta, 80. 

 Pupilla muscorum, 247. 

 pyramidata, 465. 

 Pyrgulifera, 84. 



Radix, 88, 122-125, 126, 162, 163, 178, 

 179, 199, 421, 443, 452, 454, 457. 



randolphi, 1, 179, 441, 443, 452-457. 



raphidia, 149. 



Recluzia, 463. 



reflexa, 1, 2, 4, 6, 7, 9, 17, 20, 22, 46, 

 50, 51, 94, 96, 109, 298, 312, 323-329, 

 3^-345, 347, 348, 351, 353-357, 359 

 361-363, 465. 



reflexis, 333. 



reticulata, 466. 



retusa, 467. 



Rissoa, 28. 



roseolabiata, 149, 314. 



rowellii, 303, 323 337, 349, 362-364. 



rugosa, 463. 



rustica, 877, 268-270, 288. 



sanctaemariae, 21, 24-27, 149, 154, 156- 



160. 



Sandria, 127. 

 scalaris (Walker), 341. 

 scalaris (West.), 455. 

 scudderi, 100, 311. 

 Segmentina armigera, 20. 

 senegalensis, 371. 

 septentrionalis, 301, 305. 

 sericata, 391. 

 serrata, 409, 410. 

 shumardi, 99, 101. 

 shurtleffi, 329, 330, 332. 

 sieverti, 101, 311. 

 similis, 91, 96, 101, 110. 

 SIMPSONIA, 126, 199, 200, 236, 296, 



297. 



smithsoniana, 227-229, 234. 

 solida, 203, 382, 390, 391, 407, 444, 



447, 448, 449. 

 solidula, 371, 375. 



sonomaensis, 1, 213, 222, 223, 224, 225. 

 sordidus, 303, 305, 313. 

 spadicea, 463. 

 speciosa, 137. 

 Sphaerium, 21, 28. 



occidentale, 19, 233. 

 Spirogyra, 20, 21. 

 Stagnalis, 1, 2, 4, 6, 7-9, 13, 15, 17, 



27, 28, 32, 33, 39, 41, 42, 44, 46, 48, 



52, 54, 63, 67, 84, 102, i?<5-157, 161, 



162, 166, 168, 180, 191, 200, 357, 384, 



431, 436. 

 Stagnicola, 94, 96, 105, 110, 124, 126, 



127, 163, 179, 199, 234, 235, 296, 



297, 298, 307, 347, 369, 373, 403, 



452, 458, 461. 

 STEARNSI, 53, 84, 102, 146. 

 sterkii, 20, 241, atf-250, 258, 267. 

 Stolidoma, 89. 

 strigata, 382. 

 strigosa, 171-174, 382. 



