Lower Heldeebekg Fauna. 295 



several layers of the coenosteum. They are united at more or 

 less regular intervals by concentric partitions which have the 

 porous structure above described. These concentric laminae 

 appear to be composed of inosculating fibers forming a retic- 

 ulate skeleton, and not of lateral arms given off in a whorl 

 around each pillar as in the genus Aotinostroma. Vertical 

 sections through a monticule show that the radial pillars are not 

 parallel as elsewhere, but are inclined at a slight angle away from 

 the imaginary axis of the monticule. 



This species agrees well with the figures and descriptions of 

 Syringostroma densum, except that the cut ends of the radial pil- 

 lars are not distino^uishable in tano^ential section. This seems to 

 be the common species at Cedarville, N. Y., and is readily 

 recognized by the number and prominence of the mamelons. 



Horizon. — Lower Fentamerus limestone. 



Locality. ~ Cedarville, N. Y. 



Syringostroma foveolatum, sp. nov. 

 Plate VI, figures 8, 9. 

 Coenosteum massive and of large size. Outer surface and 

 point of attachment not known. Division into latilaminae usually 

 apparent. In one specimen the latilaminse are folded into regu- 

 lar hemispherical elevations, having a diameter of about 50 mm. 

 Kadial pillars continuous and usually large. Viewed in vertical 

 section, the laminae are thick and^ the interlaminar space narrow. 

 Tangential sections show the laminae to have a dense structure, 

 but the organism may still be referred to the Milleporoid type. 

 The pores, which in S. centrotum appeared as transparent ver- 

 miculate patches, in this species are represented only by minute 

 spots, sometimes connected by transparent thread-like bands. 

 The skeleton fibers are large, with fine reticulations, giving the 

 tissue as a whole a dense consistency. The concentric laminae, 

 likewise, are unusually thick and heavy, the vacuoles of small 

 size and the intercolumnar spaces minute. Astrorhizee are fre- 

 quent, and well-developed monticules appear to be present, chiefly 

 associated with astrorhizae. They are indicated in the section by 

 a darker shading, but their elevation is so slight that tangential 

 sections often show the astrorhizae equally well on all sides. The 

 monticules sometimes have tubular axes. When weathered, the 



