280 G. W. SHRUBSOLE ON THE BRITISH 
FENESTELLA oRASSA, M‘Coy, Syn. Carb. Foss. Ireland, pl. 29. fig. 1. 
Fenestella laxa, Phill., Geol. Yorks. pl. 1. figs. 26-30. 
In point of size of interstice &e. this is the largest of the British 
species. Both Phillips and Prof. M‘Coy have described it, the 
former imperfectly, the latter with care and accuracy. Prof. M‘Coy 
says that his species is allied to that of Phillips, but possesses dis- 
tinct features ; in other words, his specimen was not so much worn 
down as that of Phillips. Prof. M‘Coy’s is by far the fullest and best 
description of this species, and I propose to retain the name given 
to it by him. 
FENESTELLA PoLyporaTA, Phill., Geol. Yorks. pl. 1. figs. 19, 20. 
Fenestella multiporata, M‘Coy, Syn. Carb. Foss. Iveland, pl. 28. 
fig. 9. 
This species in size is intermediate between Fenestella crassa, 
M‘Coy, and Fenestella plebcia, M‘Coy. Both Phillips and M‘Coy 
describe the denuded form of the species. M<‘Coy based the difference 
between the two species upon the absence of keel in Fenestella 
polyporata, Phill., and its presence in Fenestella multiporata, M‘Coy, 
which means that /. polyporata had been rather more denuded than 
F. multiporata. The almost perfect remains of an individual of 
this species which I have recently discovered have the cell-pores 
prominent and projecting, and the keel with spiny processes at 
intervals. As Phillips has fairly drawn the denuded form, it is only 
right that the name which he gave to it should be retained. 
FrnEstELLA NopuLosa, Phill., Geol. Yorks. pl, 1. figs. 31, 32, 33. 
Fenestella frutex, M‘Coy, Syn. Carb. Foss. Ireland, pl. 28. fig. 10. 
F, bicellulata, R. Eth., jun., Mem. Geol. Surv. Scotland, sheet 23, 
Tn IOI 
Actinostoma fenestratum, Young, Q. J. G. S. vol. xxx. p. 681. 
In size of interstice this interesting species occupies a midway 
position between Fenestella membranacea, Phill., and Fenestella 
plebeia, M‘Coy. It is not so common as the latter. It is very 
regular in its mode of growth, and is altogether an object of con- 
siderable beauty. Its early growth much resembles a tiny shrub, 
as mentioned by Prof. M‘Coy. In this stage it has a distinct stem 
or footstalk with parallel interstices having dissepiments describing 
a series of semicircles around the base. This is the Fenestella frutew, 
M‘Coy. The mature but worn-down form is the Fenestella nodu- 
losa, Phill. As we approach the more perfect condition of the 
polyzoon we have the Fenestella bicellulata, R. Eth., jun., with 
spiny projections on the keel. In Actinostoma fenestratum, Young, 
as before remarked, we have possibly its full development and the 
true type of the species. It is characterized by round and promi- 
nent pore-cells with circular mouths set with eight denticles, and a 
keel studded with spiny processes. Examples of this variety I have 
found in all stages of mutilation; step by step have the various 
