175 
G. W. Lee — Irepostomata. 
Comparable species. —Of the other 7abuliporae with laterally perforate tabulae, the 
only one to share with T. wexfordensis the character of having zooecia falling obliquely on 
the surface, is T. crassimuralis , whose thick walls afford a ready distinguishing feature. 
Observation. —The original of pi. xvi., fig. 7, is preserved in the Collections of the 
Geological Survey of Ireland. 
Tabulipora debilis sp. nov. 
Plate XVI, fig. 8. 
Description. —(a.) External characters. In the two specimens that have come to 
hand the zoarium is hollow and tapers appreciably, the diameter being 1 cm. near the 
base of the zoarium, and only 8 mm. above the base. The surface is not shown. 
(b.) Internal structure. The zooecia—of which there are some forty along a distance 
of 1 cm.—are attached to the epizoarium along a very small portion of their course and 
soon assume a direction perpendicular to the long axis of the zoarium. The walls are 
hardly thicker in their peripheral portion than in the axial region. 
The tabulae are somewhat more than a zooecial diameter apart and extend only partly 
across the cavity. 
In tangential section the extreme thinness of the walls is well shown, the zooecia 
having consequently a polygonal outline. Acanthopores occur at the junction- 
angles only. 
Distribution. —The illustration is from one of two specimens in the Nicholson 
Collection, which are from Stebden Hill, Cracoe, near Skipton, Yorkshire. 
Observations. —Nicholson labelled these two specimens cf. Verticillopora dubia 
M‘Coy. From the above description it will be seen that the resemblance is merely one 
of zoarial shape. 
The remarkable thinness of the walls distinguishes this species from all the other 
members of the grqup described here. 
Tabulipora spp. 
Two forms too insufficiently represented to warrant a separate description may be 
recorded here. Both belong to Section B of Tabulipora , which thus appears to be the 
richest in species in the British Carboniferous rocks. 
22239 
F 
