CfiANIA GEANOSA, Hall. 



Page 835. 

 Fig. 11. A somewhat distorted upper valve ; showing the finely granulose 



surface. 

 Fig 13. A portion of the surface enlarged, x 20. 

 Hamilton group. CenUrfield, N. Y. 



Crania favincola, Hall. 

 Page 336. 

 Fig. 13. A lower valve, slightly broken about the posterior margin, but show- 

 ing the very large posterior muscular impressions, the deeply impressed 

 anteriors with sharply elevated margins and median fulcrum ; also, the 

 radiating paUial sinuses. The shell is attached to a specimen of Favo- 

 sites pirum, Davis. 

 Hamilton group. Crab Orchard, Kentucky. 



Crania pulciiella, Hall. 



Page '335. 

 Fig. 14. An individual attached to a valve of Orthis. 

 Lower Helderberg group. Near Clarksville, N. Y. 



Ceaniella Ulrichi, Hall. 



Page 336. 



Fig. 15. A cast of the interior of a lower valve, somewhat restored at the 

 right ; showing the strong anterior and very obscure posterior adductor 

 scars and the marks of the vascular sinuses. The shell is convex and 

 shows no evidence of attachment, though the external surface is covered 

 with bryozoan growth, x 1.5. 



Fig. 16. An internal cast of the upper valve. The sigmoid vascular impres- 

 sions are simpler than elsewhere observed. The scars of the dorsal adjust- 

 ers and of the muscles accessory to the anterior adductors are also shown; 

 X 1.5. 

 Trenton limestone. Minneapolis, Minnesota, 



Pholidops patij^a, Hall. 



Page 337. 

 Fig. 17. The exterior of a valve, showing the lamellose growth-lines, crossed 



by fine, interrupted radiating striae, x 4. 



Fig. 18. The interior of a ventral (?) valve. X 4. 



Fig. 19. The interior of the opposite valve, x 4. 



Corniferous limestone. DeCeivville, Ontario, 



Pholidops CA^LcaoLA, Hall. 

 Page 337. 

 Fig. 20. The interior of a dorsal (?) valve, showing the terminal beak, the sub- 

 apical area and the character of the muscular scars, x 2. 

 Corniferous limestone. Falls of the Ohio. 



b79 



