Fauna of the Morrow Group 
131 
Genus DICTYOCLADIA n. gen. 
Description. Zoaria poriferous on one side only, pinnate or 
loosely fenestrated expansions consisting of primary branches 
with numerous lateral branches proceeding obliquely from their 
opposite margins, some of which may be nearly or quite as strong 
as the primaries and in turn give off lateral branches; lateral 
branches united at intervals by the union of non-poriferous 
pinnae from adjacent branches. Zooecia in three or more rows 
along primary and lateral branches; reverse or non-poriferous 
side with scattered dimorphic pores. 
Remarks. Dictyocladia differs from Ptilopora in that the 
zooecia occur in more than two ranges. Like Septopora it is 
characterized by the presence of accessory pores on the reverse 
side of the branches. 
Genotype: Dictyocladia triseriata n. sp. 
Dictyocladia triseriata n. sp. 
Plate VII, figures 10, 10a. 
Description. Zoarium a loosely reticulated expansion consist- 
ing of primary, secondary, and tertiary branches connected by 
occasional non-poriferous dissepiments. Primary branches rigid, 
0.7 to 0.9 mm. in width; secondary branches proceeding from 
them laterally, generally alternately, 6 or 7 in a centimeter on 
either side, at an angle of 50° to 60°, normally about 0.5 mm. in 
width but with about one in four as strong as the primary 
branches; these in turn give rise to tertiary branches similar 
to the intermediate secondary ones; branches broadly rounded 
on the reverse and longitudinally striated, gently convex on the 
obverse face. Dissepiments somewhat irregularly situated, pro- 
ceeding obliquely across the space between adjacent parallel 
branches and giving rise to trapezoidal or rhomboidal fenes- 
trules ; dissepiments averaging 0.2 mm. in width and 0.8 mm. in 
length, expanded terminally ; 5 or 6 fenestrules in 1 cm. Zooecia 
in 3 ranges along the branches, dissepiments commonly non- 
poriferous, apertures circular, 2 or more diameters apart in the 
rows, 17 or 18 in 5 mm. ; small circular accessory pores scattered 
irregularly over the reverse side of the branches. 
Horizon and locality. Hale formation: East Mountain, Fay- 
etteville, Arkansas (Station 136). Brentwood limestone: near 
Fayetteville, Arkansas (Station 135). 
