PERMO-CARBONIFEROUS FENESTELLID®. 195 
increasing in width opposite the cross-bars, and very much 
so before their bifurcation, which is fairly frequent, giving 
the species a fairly spreading habit. Cross-bars thinner 
than the branches, distinct and regular. The fenestrules 
are slightly oval or circular, occasionally shorter than they 
are broad. The non-celluliferous surface of the branches 
is covered with longitudinal striations. 
This is a strongly marked species, the rounded broad 
fenestrules giving it a definite identity. . Though provision- 
ally referred to F. internata, I am somewhat dubious, and 
quite expect that on further material being obtained, it 
will prove to be new. 
Measurements:—In 10 mm. longitudinally, 13 to 14 
cross-bars, and transversely 12 to 13 branches. Length of 
fenestrules ‘5 to °6 mm. width °5 to °75 mm. 
Locality and Horizon:—Allandale (Lower Marine Series). 
FENESTELLA EXSERTA sp.nov. (PI. VII, figs. 1, 2, XII.) 
Description :—Branches relatively of medium thickness, 
rather close together, separated by often less than their 
own width, parallel, bifurcating rarely. Cross-bars rounded, 
very much thinner than the branches. Fenestrules sub- 
oval to nearly rectangular, elongated, four or five times 
longer than broad. In one specimen, Pl. XII, fig. 1, what 
has evidently been an accidental fracture during the life 
of the colony, has been bridged over by several thickened, 
non-cell bearing, very much elongated dissepiments. Non- 
celluliferous surface not actually known, but from casts 
evidently faintly striated. Cells in two rows, their aper- 
tures small, alternating, separated from each other by about 
three times their width. The edges are well exserted, so 
much that at times they are almost tubular, with the mouths 
directed obliquely upwards. The carina is not distinct from 
+ Lonsdale, (1) p. 181; (2) p 269, pl. 9, fizs. 2, 2b. 
