135 
breadtli equals the diameter of their branches ; the cells are small, number 
two or three to each fenestrule, and are separated by a scarcely apparent keel. 
According to Lonsdale, the posterior surface is slightly granular. 
Relations and Differences. — This species bears some resemblance to 
F. pleheia, but it differs from it by the small number of cells to each fenes- 
trule, and by the granulations of its exterior surface, which last is striated in 
F. pleheia. 
Horizon and Localities. — According to Lonsdale, it is found at Mount 
Wellington, Tasmania, and at Patrick’s Plains and Raymond Terrace, New 
South Wales. Lana found it at Glendon, and Mr. Clarke in the Ichthy- 
odolurite Range, on the Kama, in a grey limestone. 
Penestella Morrisii, McCoy. 
Fenestella Morrisii, McCoy, 1814, Synop. Carb. Foss. Ireland, p. 202, pi. 28, fig. 13. 
„ „ A. d’Orbigny, 1850, Prodr. Pal., I, p. 152. 
„ „ J. Morris, 1851, Cat. Brit. Foss., p. 123. 
The coencEcium is fanlike, or more or less arborescent ; the branches 
bifurcate several times before reaching the uj)per margin ; the fenestrules are 
often irregular, though generally affecting the rectangular form ; the cross- 
bars are very thin and sub-equidistant ; the cells, numbering six on each side 
of a fenestrule, are very distinct, and are surrounded by a slight thickening ; 
the median keel separating them is not strongly marked. The posterior 
surface of the branches is smooth. 
Horizon and Localities . — This species, which is not uncommon in the 
upper beds of the Carboniferous Limestone near Cork, Ireland, was found 
by Mr. W. B. Clarke in a greyish argillaceous limestone at Burragood, on 
the Paterson, associated with the species following, and with Rliynchonella 
pleurodon, Phillips, and a large number of fragments of Crinoid stems. 
Penestella gracilis ? J. D. Dana. 
Fenestella gracilis ? J. D. Dana, 1819, Geol. Wilkes’ U. S. Explor. Exped., p. 711, pi. 11, 
fig. 4. 
I am not perfectly certain that this species is identical with that 
described and figured by Lana. It is remarkable for its dendritic form and 
its slender branches. These branches have no regularity either in direction 
