(iLOCllIDIA OF FRESHWATEll MUSSELS. 9 



aaa. Depth proator than lonpth. 



Symphynola complanata, 0.3J0 l)y 0.320 mm. (fig. 6). 

 Symphijnola costata, 0.385 by 0.390 mm. (fig. 7). 

 Alasmidonta Iruncalu, 0.350 by 0.380 mm. (fig. 42). 

 Proptera type: 



CJKuhidium varying greatly in size in the different species; axe-head shape; with 

 two spines, one at each of the ventral corners of the shell, or sjaneless. 



1. Glochidium with spines. 



a. Size large. 



Lampsilis alala, 0.220 by 0.380 mm. (fig. 8). 

 aa. Size rather small. 



Lampsilis capax, 0.105 by 0.185 mm. (fig. 9). 



2. Glochidium without spines (?). 



aaa. Size small. 



Lampsilis Ixvissima, OTIOO by 0.155 mm. (fig. 10). 

 Lampsilis type: 



Glochidium semicircular, or semi-ellii)tical; ventral margin rounded; no spines 

 present. 



1. Glochidium semi-elliptical; ventral margin rounded. 



a. Hinge line short and evenly curved, or undulate. 

 b. Size large. 



Plagiola securis, 0.230 by 0.330 mm. (fig. 14). 

 Lampsilis iris, 0.240 by 0.300 mm. (fig. 46.) 

 Lampsilis luleola, 0.250 by 0.290 mm. (fig. 15). 

 Lampsilis subrostrata, 0.270 by 0.330 mm. (fig. 16). 

 Lampsilis recta, 0.220 by 0.280 mm. (fig. 17). 

 Lampsilis ligamentina, 0.220 by 0.260 mm. (fig. 18). 

 Obovaria retusa, 0.240 by 0.295 mm. (fig. 47.) 

 Quadrula grani/era, 0.290 by 0.355 mm. (fig. 19). 

 Quadmla pustulosa, 0.230 by 0.290 mm. (fig. 20). 

 66. Size medium. 



Lampsilis anodontoidcs, 0.185 by 0.210 mm. (fig. 21). 

 Lampsilis fallaciosa, 0.200 by 0.240 mm. (fig. 22). 

 Lampsilis higginsi, 0.210 by 0.260 mm. (fig. 23). 

 Lampsilis trabalis, 0.193 by 0.255 mm. (fig. 40). 

 Lampsilis ventricosa, 0.205 by 0.255 mm. (fig. 24). 

 Obovaria ellipsis, 0.210 by 0.265 mm. (fig. 25). 

 Quadrula metanevra, 0.175 by 0.200 mm. (fig. 26). 

 Quadrula pustulata, 0.200 by 0.250 mm. (fig. 27). 

 666. Size very small. 



Lampsilis gracilis, 0.070 by 0.095 mm. (fig. 28). 

 Plagiola donaciformis, 0.060 by 0.063 mm. (fig. 29). 

 Plagiola elegans, 0.060 by 0.070 mm. (fig. 30). 

 aa. Hinge line straight, or slightly depressed, 

 c. Size small. 



Tritogonia tuberculala, 0.085 by 0.100 mm. (fig. 31). 

 la. Ventral margin obliquely rounded. 

 aaa. Hinge line long. 

 d. Size large. 



Quadruh heros, 0.260 by 0.340 mm. (fig. 32). 



