EXPLANATION OF PLATE XLI.B. 



PAGE 



Figs, i, ia, ib. POTAMOLITHUS PHILIPPIANUS Pils. Front and back views of 



the type . . . 60 1 



Fig. 2. POTAMOLITHUS BUSCHII (Ffld.) . . . . . . 580 



Fig. 3. POTAMOLITHUS RIBEIRENSIS (?) . . . . . . 584 



Fig. 4. POTAMOLITHUS LAPIDUM ELATIOR 588 



Figs. 5, 6. POTAMOLITHUS RIBEIRENSIS Pils 584 



Figs. 7, 7<z. POTAMOLITHUS CHLORIS . . . . . . . 579 



Figs. 8, 8a. POTAMOLITHUS INTRACALLOSUS 584 



Figs. 9, 10. POTAMOLITHUS PARANENSIS 589 



(VOL. m) 



