OF THE COUNTIES OF NORTHUMBERLAND AND DURHAM. 261] 
cription we may add that the outer surface is covered with 
minute tubercles, arranged in circles round the mouths of the 
cells. It is not uncommon at Tunstall. 
Orper. ASCIDIOIDA. 
Faminy. EscHarIp#. 
40. FENESTELLA (Mill.), Lons. 
1. F. anceps, Schloth. 
Ceratophytes anceps, Schloth., Mun. Ak. vi., pl. 2, f. 7. 
Gorgonia anceps, Goldf. Petrif., p. 98, tab. 36, f. 1 a, b, ¢, d ; 
Geol. Tr. iii., 2nd ser., pl. 12., f. 7. 
In Magnesian-limestone ; not uncommon. Tunstall, Hum- 
bleton. 
In this coral the longitudinal branches are not connected 
with each other by transverse processes, as in most of the species 
of this genus, but they are separate, frequently bifurcated, with 
short opposite lateral branches springing from the sides. The 
stem of the coral is flattened, covered on one side with four rows 
of cells arranged alternately, with a slightly elevated ridge be- 
tween each row. The cells are cylindrical, and curve over each 
other in the stem of the coral. 
2. F. ramosa, King. 
Hornera ramosa, King, Geol. Russ. i., p. 221? Geol. Tr. 
2nd ser., iii., pl. 12, f. 5. 
In Magnesian-limestone ; rather rare. Humbleton, Tunstall. 
This species is figured, but not described, in the Geological 
Transactions. It is more bifurcated than the former, and is 
also destitute of the numerous short lateral branches. 
3. FB. antigua, Goldf. 
Gorgonia antiqua, Goldf. Petrif., p. 99, tab. 36, f. 3a. 
Coral, with the branches very small, frequently bofur- 
cated and sharply angulated on the poriferous face; meshes 
nearlyrectangular, twice as wide as the branches; cells small, 
internal, 2 rows separated by an angulated ridge, the mouth 
of each cell furnished with a cup-like process ; transverse 
branches, not cellular, alternate, 2 or 3 cells distant ; re- 
verse smooth, or slightly furrowed longitudinally. 
