PLATE 36 A. 



Fig. 1. 521. 3. Heliolites pyriformis? (Pag. 133.) 



1 a. A weatliered vertical section of a hemispheric mass, showing the tubes partially in relief upon the sur- 

 face, with intersjjaces more abraded. 

 1 b. An enlargement of several tubes, showing the structure of the interior. 



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

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



the intercellular spaces. 

 I e. An enlargement from fig. 1 d, showing the structure of the surface and the openings of the cells. 

 1 /. The base of a weathered calcareous specimen, where the lamellae 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 fragment where the walls of the tubes are preserved, the elevated edges appearing to be produced by 



twelve j)oints or granules, with here and there slight evidences of rays. 

 1 i. Tlie same enlarged, showing more distinctly the characters mentioned, and also the unequal 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 weatliered surface, showing the exterior and interior surface of these cells. 

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



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 n. A transverse section, natural size; the rays for the most part obliterated. 

 2 6. A part of the same enlarged. 



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

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



