G. W. Lee — Treposiomata. 
181 
Distribution. —The original of pi. xvi., figs. 13-15, is from the Lower Limestone 
of a locality 1|- miles N. of Croagh, Townlancl of Cloonoul, Limerick [936c]. The 
other specimen is also from the Lower Limestone, and was found in a railway-cutting in 
the Townland of Curraghbeg, Limerick [983c]. Both are preserved in the Collections 
of the Geological Survey of Ireland, 
Dyscritella ambigua sp. nov. 
Plate XYI, figs. 11, 12. 
Description. —(a.) External characters. In the two specimens at hand the zoarium 
consists of a solid cylindrical dichotomous branch 7 mm. thick. The apertures, of which 
some forty occur along a distance of 1 cm., are circular and are separated by rather 
narrow interspaces occupied by sub-angular mesopores. The acanthopores are very small. 
(b.) Internal structure. The peripheral portion of the zooecia is short and at right 
angles to the surface, with considerably thickened walls, which assume in longitudinal 
sections a dendritic appearance due to the irregular intercalation of mesopores. 
Tabulas are so scarce that they easily escape detection. Although the slide from 
which a portion is figured, pi. xvi., fig. 11, is a large one nearly 2 cm. long, it shows 
altogether no more than three tabulse, in three separate zooecia. They appear as 
complete, but their true nature cannot be inferred from the aspect of such a restricted 
number. 
The ratio of axial region to diameter is 06 : 1. 
Seen in tangential sections the zooecia are sub-circular, separated by more or less 
angular mesopores. The acanthopores are small, and of two sizes which are not 
distributed according to any definite arrangement. 
Distribution. —The two specimens on which this description is based were collected 
by Mr. C. H. Cunnington, at Penwyllt, South Wales, from the topmost portion of the 
Carboniferous Limestone. Another example from South Wales came from the crags 
about 130 yards E.S.E. of Moody Nose, 2 miles S. of Warren (north limb of syncline), 
Pembrokeshire : horizon D2 [specimen E.D. 1879]. 
This species is so far only known in Scotland by a specimen from the Lower 
Limestones of Fulwood Burn, W. of Birkenhead, 3J miles S.E. of Carluke, Lanarkshire 
[specimen T. 4640°]. 
