418 PALEONTOLOGY OF ILLINOIS. 



CALLOPOKELLA Ulrich, 1882. 



("Amer. Pal. Bry." Jour. Tin. Soc. Nat, Hist. Vol. V. p. 154.) 

 (For generic diagnosis, see page 373.) 



The thick ring-like walls of the zooecial tubes distinguish this 

 genus from Diplotrypa Nich., species of which C. harrisi Ulr., 

 the type, resembles in other respects. The species next de- 

 scribed is only provisionally placed in the genus as better pre- 

 served material may show that it is not congeneric with C. 

 harrisi. 



CALLOPORELLA? NODULOSA Ulrich. 



PI. XXXIII, ng. 4-4a. 



Zoarium parasitic upon foreign bodies, (so far as observed 

 upon the valves of Strophomena,} forming patches of greater 

 or less extent; edge of zoarium inclined to turn up. Surface 

 marked with small conical monticules, a little more than two 

 mm. apart, measuring from center to center, more or less sub- 

 solid at the apex, due to the closure of the mesopores, and ar- 

 ranged in diagonally intersecting rows. Apertures circular, 

 about nine in two mm., 0.2 mm. or a little less in diameter. 

 Interspaces occupied by mesopores which are most numerous 

 in the monticules. 



The internal structure has not been observed owing to the 

 peculiar character of fossilization which has preserved the ex- 

 ternal features, but entirely obliterated the internal structure. 

 Hence the species is referred only provisionally to Calloporella. 

 The general external appearance is that of Atactoporella or- 

 toni Nich., but it wants the petaloid apertures of that species. 



Position and locality: Cincinnati group, Savanna, 111. 



TREMATOPORA Hall, 1852. 



(Pal. N. Y. Vol. II. p. 149.) 

 (For generic diagnosis, see page 373.) 



This genus was re-defined by me in my "Amer. Pal. Bry." 

 taking T. tuberculosa, Hall, the first species to follow Prof. 

 Hall's generic description, as the type. Much redistribution of 



