Vol. 6S.'] BEYOZOA FKOM THE LOWER CAEB@N1FEE0T7S. 577 



the immature region is very narrow, but not constant in extent." 

 Thezooecia are large, though not uniform in size : about thirty occupy 

 1 cm. ; the largest occur in groups, and originally they may have 

 constituted monticules at the surface, but this is somewhat worn ; 

 the apertures are polygonal. Cells with apertures much smaller 

 than the average occur occasionally, and especially among the 

 largest zooecia. The moniliform thickening of the walls is very 

 pronounced, occurring at frequent but variable distances through- 

 out the peripheral region, though at constant levels in all parts of 

 the zoarium. Diaphragms are few, very narrow, often thickened 

 along the inner edge ; almost invariably one occurs at the point 

 where the zooecial walls become thickened, and bend outwards to 

 proceed directly to the surface. Acanthopores of moderate size 

 occur singly at many of the junction-angles. 



This specimen is further characterized by the possession of 

 numerous structures of an unusual kind, which may prove to be 

 mesopores. They appear to have been cut off from the zooecial 

 cavities by outgrowths from the zooecial walls ; they occur singly 

 and in small clusters at many of the junction-angles. 



The genus StenopJiragma closely resembles Anisotrypa, Ulrich, 

 and Tahulipora, Young, in many characters ; but it differs from 

 both, in having narrow crescentic diaphragms attached only to the 

 proximal portion of the circumference of the zooecial walls, instead 

 of centrally perforated diaphragms. 



It seems advisable to alter one sentence in the description of the 

 family Batostomellidse, Ulrich, to read thus : — 



'diaphragms in the peripheral region often centrally perforated or 

 merely crescentic,' 



in order that the genus may be included in it. 



[As these notes are passing through the press we learn from the 

 Geological Survey Memoir on the ' British Carboniferous Treposto- 

 mata,' by Dr. G. W. Lee, issued on May 12th, 1912, that other new 

 species, agreeing in all essential characters with those described 

 above, have been placed in the genus Tahulipora Young, in 

 Section B, founded for their reception, since they differ from the 

 typical species of the genus as originally founded, in that 



'the perforation of the tabulae occupies a lateral position, distal in relation 

 to the general direction of growth.' 



In other words, the diaphragms are attached to the proximal or 

 lower walls of the zooecia.] 



Stenopoea compacta, sp. nov. (Figs. 11 & 12, pp. 578-79.) 



Zoarium ramose; branches solid, robust, often 8 mm. in 

 diameter ; frequently dichotomizing, the branches thus formed 

 only slightly narrower than the main branch ; many-layered, those 

 layers which are fully developed having a thickness of 2 mm. in 



Q. J. G. S. No. 272. 2 t 



