8o 
BULLETIN OF THE LABORATORIES 
ulatrix. another closely related form has fifteen lateral branches in 
lo mm. and the larger ones sometimes united by a dissepiment. 
Formation and locality: — Cuyahoga shales of the Waverly series 
at Richfield, O. 
TyENIODiCTYA INTERPOLATA, n. sp. 
(Plate XIII, Figs. 9, 9a.) 
Zoarium bifoliate, ramose; dividing dichotomously or otherwise at 
frequent but unequal intervals, the extremes noticed being 4 mm. 
and 15 mm. Branches acutely elliptical in transverse section, 2.5 to 
3.0 mm. wide, and about 0.5 mm. thick. Margins sharp, narrow, 
granulo-striate. Zooecia arranged in diagonally intersecting curved 
lines and in more or less regular longitudinal series, those near the 
border a little larger than those in the central region of a branch. The 
longitudinal arrangement is more pronounced in some examples than 
in others. Apertures elliptical, sometimes nearly circular, compara- 
tively large, averaging 0.25 mm. long by 0.18 mm. wide. When the 
arrangement is regular the ends of the apertures are separated by either 
one transversely elongated pit or mesopore or by two small ones. On 
some examples or portions of their surface the pits are more numerous 
and somewhat irregularly distributed. The interspaces or walls be- 
tween the zooecia apertures and mesopores are comparatively thin 
and obtusely ridge-shaped. Measuring longitudinally about fourteen 
zooecia occur in 5 mm.; diagonally ten or eleven in 3 mm. 
The minute internal structure of the walls is very much like that 
of T. ra^milosa^ the type of the genus. 
The intermediate pits that distinguish this species from the three 
forms upon which I established the new genus Taeniodictya in my 
forthcoming Illinois work lends this species a resemblance to Stictopor- 
ella. That genus, however, is essentially a Lower Silurian group and, 
though I place Lower Carboniferous forms under it, I am strongly in- 
clined to question the propriety of the arrangement. Until an exhaus- 
tive study o'f the palaeozoic bifoliate bryozoa is made the arrangement 
of species under the various genera must be regarded as tentative, and 
as the form under consideration presents no very marked deviation 
Irom the typical species of the proposed genus Tcsniodyctia, the wisest 
course for the present seems the one here adopted. 
Formation and locality : — Cuyahoga shales. This species was 
