PLATE XXXI 



PLEURODICTYUM LENTICULARE Hall (Page 424) 



Figure 1. — Calieal diagram of gerontio specimen ; showing en- 

 largement of second, fourtli, and eighth corallites, and the addition of 

 tertiary cells, forming a second series of peripheral calices. X S^. 

 Lower Helderberg Group, Albany county, New York. 



PLEURODICTYUM PROBLEMATICUM Goldfuss (Page 426) 



Figure 2. — Lower side of cast of corallum with epitheca removed ; 

 showing proximal extremities of several corallites. Upper edge of figure 

 represents portion of periphery of corallum. Thus, lower angle of each 

 corallite represents the point of budding from parent cell, and is con- 

 nected with it by a pore, shown for three of the corallites by dotted lines 

 from p. It will be noticed that all the pores in the angles are larger than 

 the others. Otherwise these and the initial pores cannot be distin- 

 guished from the ordinary mural pores between the flat sides of the 

 corallites. X 7. Devonian, Pelm, Germany. 



FAVOSITES EPIDERMATUS? Rominger (Page 426) 



Figure 3. — Side view of mature corallite with attached intermural 

 bud. Specimen broken from interior of a large colony, x 3J. 



Figure 4. — The same, front view, with bud removed ; showing pore 

 or mural opening (p) at lower point of attachment of bud, corresponding 

 to those indicated in figure 2. X 3^- 



Corniferous Limestone, Cherry Valley, New York. 



