PATAGONIAN EXPEDITIONS I ZOOLOGY. 



EXPLANATION OF PLATE XLI. 



PAGE 



Figs, i, la, ib. POTAMOLITHUS SYKESI Pils. Three views of type. . . 574 



Figs. 2, 2a. " " Gerontic individual . . . 574 



Figs. 3, 4, 5. POTAMOLITHUS BISINUATUS OBSOLETUS Pils. Cotypes . . 577 



Figs. 6, 6a. " " Pils. Two views of type . . 576 



F% s - 7 7 a ' " Two views of a gerontic 



individual. . . . 576 



Figs. 8, 8a. POTAMOLITHUS GRACILIS " Two views of the type. . 577 



Figs. 9, ga. " " VIRIDIS Pils. Two views of the type. 578 



(VOL. in) 



