LMATE LXVI. 



PAGE 



Fig. 1. PTILOPOBA VALIDA Ulr. (See also PI. LXV,) 623 



1. Beverse, x9, showing full length of branches on the left side. 



1 a. Obverse sid<> of a specimen preserving a small number of branches, x9. 

 The zooecia apertures on the midrib are covered by a calcareous 

 deposit. 



1 I. Upper portion of same fragment, x9. 



Fig. 2. PTLLOPOKA CYLINDBACEA Ulr 623 



2. Obverse side of an example that preserves some of the branches, natural 



size, and x9. The magnified view shows the perfect condition. On old 

 examples the rounded ridge of the midrib is less distinct. 

 Keokuk group. King's Mountain, Ky. 

 E. O. Ulrieh's collection. 



2 a. Reverse of an example from Bentonsport, Iowa. x9. 



Illinois State Museum. 

 2 6. Side view of midrib of flg. 2, x9. 



Fig. 3. PlNNATOPOKA YOUNOI Ulr 615 



Natural size, and portion x!8. 

 King's Mountain, Ky. 

 E. O. Ulrieh's collection. 



Fig. 4. PlNNATOPOBA FLEXUOSA Ulr 617 



4. A fragment of the natural size, with a portion, x!8, showing the charac- 

 ters of the obverse face. 



4 o, Small fragment showing the striated reverse side, with the accessory 

 pores, and, where abraded, the uniserial arrangement of the zooecia in 

 the pinna. 



4 b, 4 c. Two fragments of the natural size. 

 King's Mountain, Ky. 

 E. 0. Ulrich's collection. 



Fig. 4 d. PlNNATOPOKA STBIATA Ulr Wl? 



A specimen of the natural size. This was at first supposed to be the 

 same as P. flexuosa, but thin sections, prepared subsequently to the 

 printing of the plates, prove it quite different. 

 Keokuk group, Bentonsport, Iowa. 

 Illinois State Museum. 



