Plate LXV Continued. 



PAGE. 



Fig. 5 c. PTILOPOBA sp. 



The basal part of a strong midrib that appears to be bifurcate. Inves- 

 tigation shows that this is not so. The branches had been broken 

 away during life, as the cicatrices are in most places covered with a 

 thick deposit of calcareous material. The little fragment of net-work 

 remaining on the left side shows thick dissepiments and somewhat 

 flexuous branches, two features in which it agrees with P. acuta. The 

 acute angle at which the branches arise also point to that species. 

 Illinois State Museum. 



Fig. 6. SPHBAGIOPOBA PABASITICA Ulr 638 



3i< 6. Two specimens attached to the shell of Athyris subtilita Hall, x!8. They 



represent at the same tiino the largest and the smallest seen. 

 6 a. Specimen of the average size, x!8, growing upon the support of Lyro- 

 pora subnuadrans Hall. It shows the usua! appearance of tho Chester 

 . form. 



Chester, 111. 



E. O. Ulrich's collection. 



SSI) 



9tfl ft 



Ilirt iU -.. 



!,(: !.. . 





