130 
Kirtley F, Mather 
sepiments, 9 or 10 of which occur in a centimeter; reverse face 
of branches striated and irregularly rounded with nodiferous 
swellings occurring at unequal distances along the middle. Dis- 
sepiments arching or sub-angular as though formed by the union 
of pinnae given off from adjacent branches, depressed somewhat 
below the level of the branches on the reverse side, slightly nar- 
rower than the secondary branches and expanded terminally. 
Fenestrules varying in shape from oval through sub-quadrate 
to sub-crescentic, from 0.5 by 0.4 to 0.9 by 0.5 mm. in size, and 
from 7 to 10 in 1 cm. Zooecia normally in two alternating 
ranges along branches and dissepiments, with 17 or 18 in 5 mm. 
on the former and from 4 to 6 on each of the latter; accessory 
pores on the reverse side, small, ordinarily with 2 situated at 
either end of each dissepiment though in many cases one or both 
may be absent. Obverse not known. 
Remarks. This form is comparable to but one of the previ- 
ously described members of the genus, S. hiserialis-nervata. It 
is distinguished from that species by the greater angle between 
primary and secondary branches, the nodiferous irregularities 
of the reverse side of the branches, and the smaller number of 
zooecia in unit distance. 
Horizon and locality. Brentwood limestone: near Fayette- 
ville, Arkansas (Station 134). 
Genus ACANTHOCLADIA King 
Acanthocladia sp. 
Three fragments of a bryozoan, preserved in large part as 
impressions in shale, although indeterminable specifically, are 
referred confidently to the genus Acanthocladia. The zoarium 
consists of a narrow stipe 0.7 to 0.9 mm. in width giving off at 
regular intervals pinnate branches which are commonly, though 
not invariably, alternating. The pinnae, 7 of which occur in 
1 cm., are 0.4 to 0.6 mm. wide and 2 to 3 mm. long. Zooecia in 
3 ranges on the pinnae and probably in 5 ranges on the central 
stipe. 
Horizon and locality. Morrow formation: near Ft. Gibson, 
Oklahoma (Station 296). 
