THIRTY-EI«IIT SPECIES OF UNIOMD.V: 49 



Mauoaritana MAROINATA, Lea, fig. 27. Subtriangular ; dorsal line straight, rather long; side margins 

 much inflated above, very much compressed and flattened below, forming an obtuse angle at the base; 

 basal margin obtusely angular, furnished with a hook. Color white. A hook is placed on the inside 

 of the angle of each valve at the base. Part of the second valve is represented. Fig. 27* is the hook 

 much magnified, rather broad at the base, and terminated by an arrow-headed point. There are two 

 rows of rather large granules, decreasing in size at the point. Part of the second valve is represented. 

 Columbus, Ohio. 



Margaritana trianoulata, Lea, fig. 28. Subtriangular ; dorsal line rather long, slightly curved up- 

 ward in the middle ; side margins much inflated above, compressed and flattened below, forming a very 

 obtuse angle at the base ; basal margin subangular, and rounded at the point ; clear white. Could 

 not observe any hooks. Chattahoochee River, Georgia. 



Margaritana complanata, Lea, fig. 29. Subtriangular; dorsal line rather long, slightly curved upward 

 in the middle ; side margins very much inflated above, compressed and flattened below from the mid- 

 dle, forming an obtuse angle at the base ; basal margin obtusely angular at the point, furnished with a 

 hook; color brownish. A hook is placed on the inside of the angle of each valve at the base. Fig. 

 29*, hook much magnified, rather broad at the base, and terminated with an arrow-headed point. 

 There are five rows of small granules which cover the face of the hook. Cincinnati, Ohio. 



Margaritana deltoidea. Lea, fig. 30. Sub-triangular; dorsal line very long and straight; side margins 

 much inflated above, slightly curved below, from the middle ; basal margin rounded, furnished with a 

 hook ; color light brown. A hook is placed on the inside of each valve at the basal point. Fig. 30*, the 

 hook much magnified, rather broad at the base, and terminated with an arrow-headed point. There are 

 five or six rows of small granules along the middle of the face of the hook. Columbus, Ohio. 



Margaritana HiLDRETniANA, Lea, fig. 31. Subrotund ; dorsal line short and slightly curved inward; 

 side margins and base forming nearly a perfect circle ; clear white. Has no hooks. This was taken 

 from the branchial uterus, apparently not quite matured. More matured specimens may have hooks, 

 jxs seems generally the case with the Margaritancc. Columbus, Ohio. 



Anodonta Lewisii, Lea, fig. 32. Subtriangular; dorsal line very long and straight; side margins round 

 above, compressed and flattened below, forming a very obtuse angle at base ; basal margin obtusely an- 

 gular at the point, furnished with a hook ; color light brown. A hook is placed on the inside of each 

 valve at the basal point. Fig. 32', a hook much magnified, with an arrow-headed point. There 

 are several rows of granules along the middle of the face of the hook, diminishing towards the 

 point. Mohawk, New York. 



Anodonta ovata. Lea, fig. 33. Subtriangular; dorsal line long, slightly curved at the centre; side mar- 

 gins curved above, compressed and flattened from above the centre, forming a very obtuse angle at 

 base : basal margin rounded at the point, furnished with a hook ; color brown ; hook very similar to 

 the last described and placed on the inside of each valve at the basal point. The figure shows part 

 of the second valve. Columbus, Ohio. 



Anodonta decora, Lea, fig. 34. Subtriangular; dorsal line long, slightly curved at the centre; side mar- 

 gins inflated above and gently curved towards the base, forming an obtuse angle at base; basal margin 

 slightly rounded at the point, which is minutely serrate, furnished with a hook ; color brown. A rather 

 short hook is placed on the inside of each valve at the basal point. The figure shows part of the second 

 valve. Columbus, Ohio. 



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