PLATE XXXIII. 



PAGE. 



Pit?. 1. PACHYDICTYA EVERETTI Ulr 523 



1. An example of the natural size. 



1 a. The surface of same, x!2. 



1 b and 1 c. Two portions of a tangen.ial section, which divides the zoceoia 

 at different levels, the first showing their character near the surface, 

 the latter just above the median lamina?. 



1 d. A small portion of 1 c x50, to show the median tubuli in the cell walls. 



1 e. Vertical section, x!8. 



1 /. A small portion of a transverse section showing the large median tu- 

 buli and thin median laminae. x50. 

 Trenton limestone. Dixon, 111. 

 Collection of E. 0. Ulrich. 



Fig. 2. DlPLOTKYPA PATELLA Ulr 



2. An example of the ordinary size. 



2 n. Sectional view of same (o show its thickness. Natural size. 



2 6. Surface of same, x!2. 



2 o. Tangential section, x!8, 



2 </. Small portion of a vertical section. xI8. 



Cincinnati group, Oxford, Ohio. 



E. O. Ulrich's collection. 



458 



Fig. 3. DIPLOTBYPA? DUBIA Ulr 



3. Tangential section of this species, x!8. 



3 n. A small portion of same to show wall structure and mesopores, x50. 



3 li. Several tubes of a vertical section, x!8. 



Cincinnati group, Wilmington, 111. 



E. 0. Ulrich's collection. 



459 



Fi. 4. CALLOPOKELLA NODULOSA Ulr 418 



4. The only example seen. Natural size. It is attached to a fragment of 



Strophomena. 

 ^ n. Surface of same, x!2. 

 Illinois State Museum. 



Fig. 5. CALLOPOKA SUBNODOSA Ulr 417 



5. A fragment of the ordinary size and usual character. Natural size. 

 5 o. Surface of same, x!2. 



5 I. Tangential section, x!8. The right half cuts the cells nearer the surface 



than the left. 

 5 c. Portion of vortical section, showing the tabulation of the tube s, x!8 



Cincinnati group, Blanchester, Ohio. 



E. O. Ulrieh's collection. 



