PATAGONIAN EXPEDITIONS I ZOOLOGY. 



EXPLANATION OF PLATE XXXVIII. 



FACE. 



Figs, i, i a, \b. POTAMOLITHUS RUSHii Pils. Adult stage. Type . . 599 

 Figs. 2, za, 26, 3. POTAMOLITHUS MICROTHAUMA Pils. Type and a smaller 



specimen ......... 597 



Fig. 4. POTAMOLITHUS RUSHII Pils. Neanic stage, diam. 3 mm. . 599 

 Fig. 5. POTAMOLITHUS DINOCHILUS Pils. Adult, seen obliquely 



from above ......... 595 



Figs. 6, 6<2. POTAMOLITHUS HATCHERI Pils. Type. .... 594 



F' s - 7> 7 a > 7 & POTAMOLITHUS DINOCHILUS Pils. Three views of the type 



(fig. 5 represents the same specimen) . . . 595 



Fig. 8. POTAMOLITHUS DINOCHILUS Pils. Neanic stage. . . 596 



(VOL. in) 



