PLATE X. 



I'AGE. 



Fig. 1. Fenestella multiporata? 274 



la. A portion of the polyzoum, ahowinf; the non-poriferou8 side. Natural size. 



16. A araall portion of the same. ma<;niHed to show the surface striae, and the relative sizes 



of the fenestrules, branches, and dissepiments. 

 Ic. Poriferous side of same, to show the number and proportional size of the pores, with their 



prominent margins. 



Fig. 2. FENESTE4.LA DELICATA 273 



2a. A portion of the polyzoum. natural size, non-poriferous side. 



26. A small piece of same magnified. 



2c. A. small fi-ao:ment, more highly magnified, to show small nodes and nearly obsolete strise 



on this aide. 

 2d. Another fragment, still more highly magnified, to show the pores and subnodose mesial 



carina. 



Fig. 3. Productus 283 



View of ventral valve. 



Fig. 4. Productus 282 



4a. A side or profile view of cast of ventral valve. 



46. Front view of same. 



4c. Another view, the same specimen represented by fig. 4a, turned so as to show a cast of the 



interior of the dorsal valve and of the umbonal region, muscular impressions, etc., of 



the ventral valve. 



Fig. 5. Hemipronites crenistria ._. 279 



5a. A dorsal view of an internal cast, showing, oblicinely, the cardinal area, pseado-del- 



tidium, etc. 

 56. A ventral view of game, showing cast of muscular scars. 

 5c. An outline lateral view of same. 

 5d. Surface strias magnified to show the minute, regular lines of growth. 



