PLATE 36 A. 



Fig. 1. 521. 3. Heuolites pyriformis? (Pag- 133.) 



1 o. A woaUiorcil vertical soctioii of a lieiaisplieric mass, showing the tubes partially in relief upon the sur- 

 face, with interspaces more abraded. 

 1 b. All enlargement of several tubes, showing the structure of the interioi-. 



1 c. An enlargement from another jiart of the same specimen, where the cylindrical tubes stand out in relief. 

 \ d. A portion of the surface of the same specimen, showing the openings of the cells upon the surface, and 



the intercellular spaces. 

 1 c An enlargement from fig. 1 rf, showing the structure of the surftice and the openings of the cells. 

 1 /. The base of a weathered calcareous .specimen, where the lamelhe and septa are nearly all obliterated, 



showing the striated interior and exterior of the tubes, 

 I g. An enlargement of a portion of the preceding figure. 

 1 A. A fmgment where the walls of tlie tubes ar<' preserved, the elevated edges appearing to be produced by 



twelve points or granules, with here and there slight evidences of rays. 

 1 i. The same enlarged, showing more distinctly the characters mentioned, and also the unccjual distances of 



these tubes from each other ; in some cases the walls being nearly or quite in contact, while in others 



they are widely separated. 

 1 fc. A weathered surface, showing the exterior and interior surface of these cells, 

 1 /. A weathered surface of a specimen preserving the cylindrical tubes, where the intercellular spaces Iiave 



been filled with crystalline matter, which has assumed a minutely tubular or cylindrical form. 

 1 / 1- An enlargement of several of the fluted cells and tubular interspaces. 



1 m. Transverse section of the same, showing the ends of the minute tubes. 



Fig. 2. 522. 4. Heliolites macrostylus. ( Pag. 135.) 



2 a. A transvci-se section, natural size; the rays for the most part obliterated. 

 2 6. A [lart of the same enlarged. 



2 c A vertical section, .showing the striated surfaces and close arrangement of the tubes. 

 2 c f. An enlargement of a single cell from 2 c. 



