Fauna of the Morrow Group 
91 
half way to the center. All are of approximately the same 
length and thickness and few are quite straight. In some sec- 
tions the cardinal septum may be distinguished by a slightly 
greater length and by the fact that the other septa show a tend- 
ency to curve so that they are concave towards it. Dissepi- 
ments are rarely present in the peripheral portion. 
In longitudinal section the tabulae are seen to be simple, flat- 
tened or very gently concave throughout the major part of their 
area, and abruptly curved downward close to their peripheries. 
They are usually about 1.5 mm. apart in the mature region. 
Remarks. Only two species of Ampiexus are known from the 
Pennsylvanian strata of North America, A. zaphrentiformis 
White and A. sp. Girty, both from the Cordilleran province. To 
the first, the species above described is evidently not closely 
related but with the second its affinities may be close. 
Horizon and locality. Brentwood limestone: near Fayette- 
ville (Station 134), and Brentwood (Station 145), Arkansas; 
Sawney Hollow, Oklahoma (Station 210). Morrow formation: 
near Ft. Gibson, Oklahoma (Stations 296 and 301). 
Genus LOPHOPHYLLUM Milne-Edwards & Haime 
Lophophyllum profundum (Milne-Edwards & Haime) 
Plate /, figures 11-13. 
1858. Cyathaxonia profunda. Milne-Edwards and Haime, Mon. des 
Polyp. Foss., p. 323. 
Carboniferous: Flint Ridge, Ohio. 
1860. Cyathaxonia profunda. Milne-Edwards, Hist. Nat. Corr., vol. 3, 
p. 331. 
Carboniferous : Ohio, 
1860. Cyathaxonia prolifera. McChesney, Desc. New Pal. Foss., p. 75. 
Coal Measures: Widely distributed in the Western States. 
1865. Cyathaxonia prolifera. McChesney, 111. New Spec. Foss., pi. 2, 
figs. 1-3. 
1866. Cyathaxonia (?) sp. Geinitz, Carb. und Dyas in Nebr., pp. 65, 66, 
tab. 5, figs. 3-4. 
Plattsmouth, Nebraska. 
1868. Cyathaxonia prolifera. McChesney, Trans. Chicago Acad. Sci., vol. 
1, p. 1, pi. 2, figs. 1-3. 
Coal Measures: Springfield, Illinois. 
1872. Lophophyllum proliferum. Meek, U. S. Geol. Surv. Nebr., p. 149, 
pi. 5, figs. 4 a-b. 
Upper Coal Measures: Nebraska City and Rock Bluff, Nebraska; 
Springfield and LaSalle, Illinois; Texas. 
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