NAIADES OF MISSOURI 7 9 



32. 5. complanata (Barnes) — (i.a) 



33. 5. coslata (Raf.) — (3. c) 

 Genus XII. Arcidens Simpson) 



34. A. confragosus (Say") — (2. c) 



(b) — Mantle connection between anal and supra-anal openings very 

 long; hinge completely absent; disk smooth; shell thin. 



Genus XII. Lastena (Raf.) 



35. L. suborbiculata (Say) — (i. b) 



36. L. ohiensis (Raf.) — (i. b) 

 Genus XIV. Anodonta (Lamarck) 



37. A grandis (Say) — (i. b) • ■ 



38. A. dakolana Frierson — (i. b) 



39. A. corpulenta Cooper — (i. b) 



40. A. Danielsii Lea — (i. a) 



41. A. Bealii Lea — (i. 2c) 



(c)— Mantle connection between anal and supra-anal openings 

 moderately long; hinge almost absent; shell rather thin, disk 

 unscupltured Genus XV. AnodonToides (Simpson) 



42. A. Ferussacianus (Lea) — -(i. b — ) 



b. — Inner laminae of inner gills with tendency to connect with vis- 

 ceral mass; mantle connection between anal and supra-anal openings 

 moderate; beak sculpture, heavy, concentric. 



(a) — Marsupium with simple ovisacs; hinge teeth rather well de- 

 veloped with cardinals sharp and prominent. 



Genus XVI. Alasmidonta (Say) 



43. A. calceolus (Lea) — (3. c) 



44. A. marginala Say — (2. c) 



(b) — Marsupium with transverse ovisacs; hinge rudimentary with 

 cardinals rounded and suppressed . . Genus VXII. Strophitus (Raf) 



45. 5. edentulus (Say) — (2. a) 



(C) — Mantle connection between branchial and anal openings present, 

 never very long; inner laminae of inner gills rarely ever entirely free 

 from visceral mass; post- ventral margin of mantle usually highly 

 differentiated with papillae, flaps, etc.; part of outer gills in most 

 genera specialized as marsupia, which, when gravid, bulging beyond 

 original edge of gills, ruptured at ventral edge of ovisacs for escape of 

 larvae; glochidia semi-circular, (Lampsilis type), or axe-head shape 

 (Proptera type), ventral margin rounded, rarely spined; bradytictic. 



Sub-Family III. Lampsilinae Ortmann. 

 a. — Marsupium with subcylindrical ovisacs; post ventral margin of 

 mantle smooth; shell sometimes with disk sculptured, sex dimor- 

 phism of shell not distinct. 



(a) — Marsupium occupying almost entire outer gill, edges folded, 

 ovisacs several, small, short. . . .Genus XVIII. Ellipsaria (Raf.) 



46. E. clintonensis (Simpson) — (3. c) 



(b) — Marsupium occupying outer gill in a few, large, long ovisacs. 



Genus XIX. Obliquaria (Raf.) 



47. 0. reflexa (Raf.) — (i. c) 



