PLATE XX. 



Fig. 1, PLATYCEiaAS TOBTUM -*vv 345 



la. A dorsal view, 

 lb. A. ventral view of same specimen. 

 ■ Ic Dorsal view of another specimen. 



Fig. 2. AvicuLOPiNNA Americana - *... 337 



A specimen flattened by preaaure. 



Fig. 3, Ptilodictya (Stictopora) carbonaria ^-*w 32& 



^o. An imperfect specimen. Natural size. 



^}>. A portion of a bnandi, magnified to shbw the pores. 



Fig. 4, Ptilodictya (Stictopora) serrata «..„ 327 



A portion, natural size, showing the serrated lateral margins. 



Fi^. ^- Synocladia biserialis «— w. 326 



■5a. A part of the polyEoam, non -poriferous side. Natural size. 

 ^. * A small part of same, magnified to show the dimorphous celts. 



Fog. 6. Macbocheilus Klipparti .^kw— » 346 



6a. A email, short specimen, with the lip broken away. 

 ' 6&. A large individnal, also having the lip broken away, and showiag the thi^ieMed inamn 



lip twisted into a prominent fold below. 

 Qc. Another view of the last. 



Fig. 7. SCHIZODUS CUNEATUS s , „ 



View of right valve. Natural size. 



