PLATE XXVIT. 



PAGE 



Pigs. 1, la. TuERiTELLA HUMEROSA Conrad 148 



1. Ventral view. 1 mile southeast of Mason Springs. 



Figs. 2, 3. TURRITELLA POTOMACENSIS n. sp 149 



Type specimens. Popes Creek. 



Pig. 4. Mesalia obkuta (Conrad) 149 



Popes Creek, 



Figs. 5, 5a, 6, 7. Vekmetus sp 150 



5. Small mass of tubes. 



5a. End of same tube, enlarged. 



6. Mass of tubes. Piscataway Creek. U. S. National Museum. 



7. Short fragment of tube from same specimen, enlarged. 



279 



