382 PALEONTOLOGY OF ILLINOIS. 



Family FISTULIPORIDJS Ulrich. 



Zoaria massive, laminar, bifoliate or ramose. Zocecia with a 

 more or less developed "lunarium," causing many modifications 

 in the form of the apertures; diaphragms horizontal. Inter- 

 spaces occupied by vesicular tissue. Cystiphragms and acantho- 

 pores wanting; eccentrically perforated opercular covers close 

 the perfect zooecial aperture. 



FISTULIPORA McCoy, Lichenalia Hall, Thallostigma Hall, 

 Didymopora Ulrich. Zoaria massive, lamellate, parasitic or 

 free, with a wrinkled epitheca below; less commonly sub-ramose, 

 the branches solid or hollow. Zocecia subradially arranged 

 about the surface maculae, with ovoid, sub-triangular, or pyri- 

 form apertures, the variations being due to the degree in which 

 the lunarium is developed; internally with thin walls and a 

 small number of complete horizontal diaphragms. Interspaces 

 smooth or granular, internally occupied by one or more series 

 of vesicular cells. 



Type: Calamopora incrustans Phillips (Fistulipora minor Mc- 

 Coy). Range, Lower Silurian to Carboniferous. 



A section of the genus that ought, perhaps, to be separated, 

 differs in having the zooecial apertures circular and the luna- 

 rium obsolete. 



Type: F. communis Ulrich. 



ERIDOPORA Ulrich, Pileotrypa Hall (pars). Zoaria thin, para- 

 sitic. Zocecia with oblique, sub-triangular or ovoid apertures. 

 Lunarium very prominent. 



Type: E. macrostoma Ulrich. Range, Niagara to Coal Meas- 

 ures. 



CHILOTRYPA Ulrich (Coelocaulis Hall.) Zoaria ramose, the 

 branches with a small, irregularly contracting and expanding 

 central tube. Zooecia with the posterior portion of the wall 

 thickest and strongty elevated hood-like, gradually thinning on 

 the sides, becoming linear at the front; the aperture elliptical 

 and oblique. Interstitial vesicles filled by a dense calcareous 

 deposit near the surface. Diaphragms few or absent. 



Type: C. hispida Ulrich. Range, Niagara to Coal Measures. 



