160 G. W. Lee — Trepostomata. 
portion immediately preceding it. There are some ten tabulm to each tube, and the 
distance separating them is approximately equal to their own diameter. 
In tangential sections the acanthopores are restricted to the junction-angles. In the 
specimens observed, their substance is not very different from that of the wall, 
consequently they are rather inconspicuous. 
The ratio of axial region to diameter is equal to 0 - 5 : 1. 
Distribution. —Numerous specimens of this species were obtained by Mr. A. 
Macconochie from a sandy limestone exposed on the shore 2J miles W. of the mouth of 
the River Nith, near Arbigland, Kirkcudbright. This limestone belongs to the 
Calciferous Sandstone Series, and is presumably of Dl age. 
Comparable species. —The course of the zooecia, which is here gentle instead of 
bending at right angles as is usually the case, distinguishes this species from the majority 
of the other British Stenoporae. Of the species so far known, the only one exhibiting 
this character in a marked degree is Stenopora tenuipora sp. nov., which otherwise differs 
considerably, having smaller zooecia characterised by their polygonal section. A certain 
amount of obliquity is shown in the zooecia of Stenopora haddingtonensis sp. nov., but, as 
already stated, the presence of mesopore-like cells suggests that the latter form may 
probably not be congeneric with the various species described here as belonging to 
Stenopora. Attention might also be drawn here to the fact that the absence of sharp 
bending occurs also in the genus Tabulipora , e.g., Tabulipora wexfordensis sp. nov. 
Observations. —That Stenopora obliqua is specifically distinct from the common 
Scotch “ Chaetetes tumidus ” was recognized by Dr. B. N. Peach who entered it as 
Stenopora arbuscula Eichwald, in the palasontological appendix to the Survey Memoir 
describing the geology of Kirkcudbright. 1 But, although the species described, here 
certainly does resemble Stenopora arbuscula in its mode of growth, it is deemed safer to 
propose a new name for it, since Eichwald’s species is an Upper Carboniferous one, the 
internal structure of which is imperfectly known. The slide figured pi. xv, fig. 5 was 
cut from a specimen labelled M. 3317 b , preserved in the collections of the Geological 
Survey in Scotland. 
