138 
Kirtley F. Mather 
Cystodictya morrowensis n. sp. 
Plate VII, figures 5-6a. 
Description. Zoarium consisting of nearly rigid, bifoliate 
branches; the primary ones varying in width from 1.3 to 1.6 
mm. and giving off, by bifurcation or more commonly by lateral 
division at intervals of 3 to 8 mm., secondary stipes, 0.8 to 1.2 
mm. wide. In cross-section the branches are regularly elongate 
elliptical in outline, the narrower ones somewhat more strongly 
curved than the broader ones. Zooecia arranged in longitudinal 
series, separated by narrow, rounded ridges, indistinct on the 
best preserved specimens but more strongly elevated on the 
worn surfaces, with 5 or 6 ranges on the broader branches and 
4 or 5 on the narrower and secondary ones; a definite oblique 
arrangement is also commonly present. Apertures small, 
oblique, 10 or 11 in 5 mm. longitudinally, peristome strongly 
elevated, crescentic on some specimens but normally complete; 
non-poriferous margins narrow but distinct. 
Remarks. This species is comparable to but one other Penn- 
sylvanian form, C. lophodes, from which it may be distinguished 
by its more elliptical cross-section, generally more numerous 
longitudinal series, and the closer spacing of the apertures. 
Horizon and locality. Morrow formation: near Ft. Gibson, 
Oklahoma (Stations 296 and 301). 
Genus COSCINIUM Keyserling 
Coscinium fayettevillensis n. sp. 
Plate VII, figure 3. 
Description. Zoarium composed of bifoliate, inosculating 
branches attached at the base to some foreign object and united 
above into a fenestrated network. Branches 3.0 to 4.6 mm. in 
width and about 1 mm. thick ; fenestrules elongate oval or some- 
what irregular in outline, 1.5 by 2.7 mm. in diameter. Zooecia 
arranged in regular, longitudinal, curving rows without definite 
oblique series, 8 or 9 ranges on each branch; the portion adja- 
cent to the fenestrules not occupied by zooecia, the non-poriferous 
area being wider in the line of the greater diameter of the fenes- 
trules than along its lateral margins. Apertures sub-circular in 
outline, directed obliquely upward, peristome not strongly ele- 
vated, lunarium not preserved in the material at hand ; 10 or 11 
