21 



PLATE XXII. 



1 Unio Blandingianus, p. 200 



2 Burroughianus, p. 197 



3 Parvus, p. 196 



4 Bialatus, p. 214 



5 Purpuratus, p. 208 



6 Membranaceus,p.202 



7 Cuprinus, p. 208 



8 Contradens, p. 209 



9 Lugubris, p. 206 



10 



11 



12 



13 



14 



15 



16 

 17 

 18 

 19 



20 

 21 



22 

 23 

 24 

 25 

 26 

 27 



Carbonarius, p. 184 



— Lecontianus, p. 188 



— Discus, p. 197 



— Parchappi, p. 212 



— Guayaranus, p. 213 



— Corrientesinensis, p. 

 212 



— Patagonicus, p. 208 



— Paraguayanus, p. 212 



— Minuanus, p. 213 



— Fossiculiferus, p. 213 



— Khombeus, p. 208 



— Decisus, p. 187 



— Sulcatus, p. 188 



— Calceola, p, 212 



— Occidens, p. 189 



— Angustatus, p. 204 



— Lanceolatus, p. 204 



— Patulus, p. 187 



28 Unio Heros, p. 175 



29 — Trapezoides, p. 176 



30 - 



Castaneus, p. 188 



Congarseus, p. 200 



Olivarius, p. 195 



Glans, p. 196 



Obesus, p. 198 



Acutissimus, p. 177 



Pustulatus, p. 178 



Asper, p. 179 



Stapes, p. 179 



Perplexus, p. 181 



Arcseformis, p. 182 



Donaciformis, p. 183 



Ziczac, p. 183 



Subovatus, p. 184 



Holstonianus, p. 213 



Fabula, p. 213 



Arctior, p. 208 



Jejunus, p. 199 



Vaughanianus, p. 208 



Arcula, p. 210 



50 Deltoideus, p. 211 



51. Lecontianus (copied 



from Lea), p. 188 



Fisherianus, p. 206 



Jayensis, p. 206 



Coccineus, p. 203 



55 Folliculatus, p. 204 



56 Vanuxernensis, p. 193 



57 



31 



32 

 33 

 34 

 35 

 36 

 37 

 38 

 39 

 40 

 41 

 42 

 43 

 44 

 45 

 46 

 47 

 48 

 49 



52 



53 

 54 



Zieglerianus, p. 193 



