26 
Striatopora, Hall. These genera differ by the fact “ that the thickening of 
the immediate joeriphcry of the calicos is carried to a mnch more extreme 
extent” in Traclujpora than in Striatopora, caused by the deposition of an 
excessive quantity of selerenchyma in the interior of the corallites. This 
results in the formation of a mnch larger extent of free surface exteriorly 
between the calices, which is ornamented with grooves and ridges. Such is 
the structure of the species about to be described, but it undoubtedly also 
approaches Striatopora in the somewhat erect, sub-angular, and polygonal 
mouths of the calices, and the highly-developed septal striae, 
A microscopic examination of this species — which it is proposed to call 
T. JFitJcinsoni, in honour of the Government Geologist — enables me to quite 
support Prof. Nicholson’s statemenP that there is no proper coenenchyma nor 
a columella in Trachypora. Lastly, it has been proposed to unite the Car- 
boniferous genus Hhahdopora with the present, a union which will receive 
some support from the geological position of T. JFilMnsoni. 
TllACKYPOEA WiLKINSONI, sp. nOV. 
PI. I ; PI. VI, Pigs. 1 and 2. 
Sp. Char . — Corallum of stout cylindrical bifurcating stems, from four 
to six lines in diameter, but increasing to nine lines immediately previous to 
l)ifurcatiou, sometimes giving off additional l)lunt abortive branches, with the 
entire free surface, like that of the parent stems, occupied by calices, and j)re- 
senting a roughened hackly appearance from their exsert mouths. Tiie latter 
are round or oval, of variable size, the larger about three-fourths of a line in 
diameter, irregularly placed as to size, arranged roughly in longitudinal 
rows, and their mouths set a little obliquely to the longer axes of the coral- 
lites, but the lower edge of each calice slightly exsert. Intercalicular surface 
extensive, ornamented with irregular vermicular ridges and tubercles, the 
former sometimes assuming a ronghly radiate appearance. Septa represented 
by very conspicuous radiating ridges within the calice mouths, separated by 
intervening deep grooves. Tabulm irregularly placed, sometimes remote, at 
otlier times contiguous, both horizontal and oblique. Mural pores small and 
irregularly distributed. 
* Tab. Corals Pal. Period, 1879, p. 104. 
