168 G. W. Lee — Trepostomata. 
specimen from the Isle of Man is preserved in the Sedgwick Museum, Cambridge 
[No. 300]. 
Quite typical examples of Tabulipora howsei occur in the Carboniferous rocks of 
Ireland. The Collection of the Geological Survey of Ireland contains a specimen 
preserved in black shale, with the indication : Tyrone, Clogher, agreeing closely with 
Portlock’s Favosites tumicla 1 which is also from that locality. More precise indications 
regarding its horizon are afforded by materials collected by Mr. W. B. Wright in the 
Bundoran district, where T. howsei occurs in the Upper Calp Shales, accompanied by a 
variant in which the proportional size of axial region to diameter is greater than in the 
typical form. 
Fully developed specimens of T. howsei are such striking objects that they could not 
possibly be overlooked by collectors. It may thus be safely assumed that the species does 
not occur in Central and South-Western England, conditions suitable to its development 
having restricted it to the North-British area, the Isle of Man and Northern Ireland. 
Comparable species .-—The large size that T. howsei attains when developed under 
favourable conditions distinguishes it at first sight from all the other British 
Trepostomatous Bryozoa. The smaller examples are distinguished from T. scotica by the 
more pronounced beading of their walls and the smaller proportions of the axial region. 
The presence in the East Kilbride district of a small form with similar wall-structure, but 
with much narrower axial region, has already been noted. A specimen -collected by 
Mr. J. Ingram from a loose block of limestone near Settle, has similar proportions, but 
indistinct beading. 
A specimen preserved in the Collections of the Geological Survey of Ireland [1989 c ] 
from the Lower Limestone of Gibbonstown, Limerick, appears to be closely related to 
T. howsei , from which it differs mainly in having thicker walls. This is the only record 
of a centrally perforated Tabulipora from Tournaisian beds. 
Species bearing a strong resemblance to 7. howsei occur outside Britain. T. arctica 
(Nich.) [ Stenoporci howsii , var. arctica Auct.] 2 from the Upper Carboniferous rocks of 
Feilden Isthmus, Lat. 82°48'N., differs mainly in having slightly smaller zooecia. The 
American fauna contains two species agreeing with T. hoivsei in the pronounced beading 
of the walls, namely 7. americana (Ulrich) and T. conferta (Worthen). The first of 
these agrees closely, differing only in the slightly larger size of the zooecia and the more 
33, p. 326, pi. 22, fig. 4. 
27, p. 289. 
