NEW FRESH WATER AND LAND SHELLS. 241 



Remarks. — The specimen for which the above description was made appears 

 to be mature. It may, however, sometimes occur larger. The beaks are too 

 much eroded to observe if they were undulated. The green predominates in 

 the epidermis in the superior part of the disk, — the inferior part is yellow. The 

 epidermis is rough from frequent crimping. 



Anodonta globosa. Plate 24, Fig. 56. 



Testa rotunda, valde inflatd, in<Bquilaterali ; valvulis tenuibus; natihus frominentibiis, undulalis; 

 epidermide viridi, obsolete radiatd; margaritd ccBruleo-albd et iridescente. 



Shell rounded, very much inflated, inequilateral; valves thin; beaks prominent and undulated; epidermis 

 green, obscurely radiated ; nacre bluish-white and iridescent. 



Hab. Concha Lake near Tlocatalpam, Mexico. Dr. Burrough. 

 My Cabinet, and Cabinet of Dr. Burrough. 

 Diam. 2.2, Length 2.9, Breadth 4 inches. 



Shell rounded, very much inflated, globose, much swollen under the beaks, 

 inequilateral, subangular behind; lines of growth divStinct and distant; sub- 

 stance of the shell very thin; margin broad; beaks very prominent, much 

 inflated, and finely undulated at the tip; ligament rather long and thin; epi- 

 dermis green with occasional interruptions of yellow; anterior cicatrices con- 

 fluent; posterior cicatrices confluent; dorsal cicatrices none; cavity of the shell 

 very deep and rounded; cavity of the beak large; dorsal line very slightly 

 curved; nacre bluish-white and finely iridescent. 



Remarks. — This is the most globose Anodonta which has been described. 

 The margin is not quite so rounded as An. suborhiculata, Say, but the shell is 

 much more inflated. It has some resemblance to An. gihhosa, Say, yet cannot be 

 mistaken for that species, on account of its being devoid of the gibbous character 

 and being more orbicular. It is somewhat angular at the anterior dorsal maro-in. 

 The undulations at the beaks are small and duplicate. Dr. Burrough brouo-ht 

 three specimens only, one of which is much older and larger than that figured. 

 Concha Lake is about twenty leagues south of Vera Cruz. 



