Bri.i.. U. S. ]i. 1'., i<)ii)-2o. 



Plati- XX. 



^ 



^ ^ ^ ^ 



^^ fl^ ni^ 





«> 4. • # 



Juveniles of 20 species of mussels found in the artificial pouds at tlie U. S. Fisheries Biological 

 •Station within two years from the time of construction of the ponds. Rcadini: from left to riKht 

 these are: 



Top row: Anodotila imbeciUis, Anctdonta cortmletila, Anodonta suborbiculala, Arcidens confragosus. 



hccond row Slropliilusedenlulus.Symphynola complanala, Lampnlis alata. Lampsilis lar.issima. 



Third row: Lampsilu capax, Lampsilis gracilis, Lampsilis reiilrkosa. Laiiipsilis lulcola. 



Fourth tow. Lampsilis sttbroslrala. Lampsilis paria. Lampsilis litiameiiliiia. Obo-.aria ellipsis. 



l-ilth row: Plaijiola donanformis. Obliiiiiaria rejtexa. QuadriiUi plicala. Qliadrula uiidata 



All reproduced natural size exceptinc the two right-hand figures in top row which are reduced 

 one-half. (Photographed by J. B. vSouthall.) 



