HYDROZOIDS AND CORALS. 117 



of the oval calycinal disk and extending nearly to the border. 

 Septa prominent ; 20 to 40 in number, with numerous rudimen- 

 tary ones. 



Horizon and localities. — Lower Carboniferous, Burlington 

 limestone : Louisiana, Sedalia. 



Microcyclus blairi Miller. 



Microcyclus hlairi Miller, 1892: Geol. Sur. Indiana, 18tb Ann. Rep., adv. 

 sheets, p. 7, pi. ix, tigs. 27-28. 



Much like Hadrophyllum in general appearance, but very 

 short and discoid. 



Horizon and localities. — Lower Carboniferous, Chouteau 

 limestone: Sedalia. 



Streptelasma corniculum Hall. 



Plate xiii, fig. 9. 



Streptelasma corniculum Hall, 1847 : Pal. N. Y"., vol. 1, p. 69, pi. xxv, figs. 



la-e. 

 Streptelasma corniculum White, 1882: Geol. Sur. Indiana, 11th Ann. Kept., 



p. 376, pi. li, tigs. 2-4. 

 Streptelasma corniculum Rominger, 1876: Geol. Sur. Michigan, vol. Ill, 



(ii), p. 142, pi. li, tig. 1. 



Oorallum simple, conical to elongate-conical, slightly and 

 regularly curved. Calyx moderately deep ; lamellae rather 

 heavy, 80 to 120 in number. Epithecal crust rather well de- 

 veloped, longitudinally striated, and often with fine traversed 

 wrinkles. 



Horizon and localities. — Lower Silurian, Trenton limestone : 

 Cape Girardeau, Cyrene ( Pike county ). 



Cystophyllum americanum Edwards &Haimb. 



Plate xiv, flgs. 4a-b. 

 Cystophyllum americanum Edwards & Haime, 1851 : Monog. Polyp. Foss. d. 



Terr. Palse. , p. 464. 

 Cystophyllum americanum Rominger, 1876: Geol. Sur. Michigan, vol. Ill, 



pt. ii, p. 183, pi. 1, fig. 1. 



Corallum of medium size, simple, conical, moderately 

 curved. Calyx deep, blistered ; radial ridges more or less ob- 

 solete. Surface of epithecal wall concentrically wrinkled. 



Horizon and localities. — Devonian, Calaway limestone : 

 Winfield (Lincoln county). 



