G. W. Lee — Trepostomata. 
169 
nearly circular shape of the perforation ; the other differs by the same characters, and in 
having stronger acanthopores. 
Nicholson’s species is mentioned by Romanowski, who appears—the text is in 
Russian—to compare it with his Stenopora lahusmi, which it certainly resembles in its 
mode of growth and strongly beaded walls. But the Russian species is depicted as 
having complete tabulae. 1 
Observations. —7. hoivsei has sometimes been recorded as Monticulipora injiata de 
Koninclc. That there are good grounds for considering the latter to be very distinct from 
the former, is shown on p. 183. 
The specimen figured, pi. xv., figs. 22-24, was collected by Mr. A. Macconochie on 
the left bank of the River Esk, a quarter of a mile N.W. of Grilnockie Tower, Dumfries¬ 
shire, from a bed situated at the horizon of the Lawston Linn Limestone [M. 648 f ]. 
Tabulipora tenuimuralis sp. nov. 
Plate XY, figs. 25-27. 
Description. —(a.) External characters. The zoarium is composed of hollow or 
solid branches from 5 to 10 mm. in diameter. Some forty-five apertures occur along 
a distance of 1 cm. They have thin partitions and are markedly polygonal in outline. 
Maculae of small cells are surrounded by apertures larger than the average. A small 
acanthopore occupying the junction-angles can be made out with the help of a strong lens. 
(b.) Internal structure. The peripheral end of the walls is at right angles to the 
surface. The walls, though showing moniliform structure, are remarkably thin. They 
are flexuous and sometimes appear as if anastomosed. The tabulas are close-set, generally 
less than their diameter apart. The perforation is not so nearly central as in the 
preceding species, but somewhat sub-central, and appears to be circular. The ratio of 
axial region to diameter, in the solid form, is 0'5 : 1. 
Seen in tangential sections, the zooecia have a polygonal outline. The acanthopores, 
moderately large, are all of the same size and generally occupy the junction-angles, 
occurring rarely elsewhere. 
Distribution. —A few specimens of the hollow form of this species, from Raven stone- 
dale, are preserved in the Nicholson Collection. A solid specimen was collected by 
Mr. Rhodes at the Eelwell Quarry, near Lowick, which is referred to the D 2 zone. 
E 
22239 
1 35, p. 192, pi. vi. 
