394 



PALEONTOLOGY OF ILLINOIS. 



Fig. U. a. tangential section of Sticto- 

 porella interstincta Ul. (Gin. gr.); b, ver- 

 tical section of same. 



Fig. 13. a, vertical section of Stictotrypa punctipora Hall (sp.). b, vertical section 

 of Stictotrypa similis Hall (sp.). c, tangential section of same. All x25. 



STICTOPORELLA Ulrich. Zoaria 

 branching, cribrose, or leaflike. 

 Zooecia with the primitive por- 

 tion tubular and unusually long. 

 Superior hemisepta wanting; the 

 inferior ones sometimes present. 

 Apertures placed at the bottom 

 of a wide sloping area. More 

 or less numerous thick-walled 

 and untabulated mesopores oc- 

 cur between the zooecia apertures 

 and line the zoarial margin. In 

 the frondose species they also form clusters. Tangential sec- 

 tions show that both the zooecia and mesopores are separated 

 from each other by a sharply defined line. 

 Type: 8. interstincta Ulrich. Range, Trenton to (?) Chester. 



INTRAPORA Hall, (Cosinella, Hall.) Zoaria cribrose, branch- 

 ing, or sub-frondose. Zooecia with moderately thin walls, which 

 are not sharply distinguished from those of the numerous tabu- 

 lated mesopores which occupy the interspaces. Apertures sub- 

 circular, without area but enclosed by faintly elevated peri- 

 stomes. A short distance below the plane of the zooecia aper- 

 tures perfect specimens show a perforated diaphragm. Meso- 

 pores usually open at the surface, but sometimes completely 

 closed by a deposit of horizontally laminated calcareous 

 matter. 



Type: /. puteolfita, Hall. Range, Devonian. 



