94 
It is, however, necessary to explain that I now know my original 
description of T. (?) Murrayi , included two distinct corals. Although 
suspected for some time, I only became convinced of this on receiving the 
National Museum specimens. In each of the examples from the Geological 
Survey collection the larger corallites ( T . (?) Murrayi restricted) are inter- 
mingled with a number of much smaller, more or less irregular tubes ; these 
I took to arise from the larger corallites as the result of repeated parietal 
budding, more than one apparent junction being present. The specimen 
from the National Museum is free of this second coral, and after a long and 
tedious examination I find that the internal structure of these tubes is purely 
cvstoid-vesicular. I, therefore, restrict the name T. (?) Murrayi to the 
larger cylindrical corallites. 
Whilst possessing one of the most important and essential characters 
of Tryplasma, the large corallites depart from the structure or typical 
members of the genus by the presence of peripheral endothecal tissue in the 
form of from one to two cycles of calcareous plates passing from one septal 
lamella to the next one, and apparently (so far as my limited opportunity for 
examination has gone) enveloped, like the septal spines, with the exception 
of the actual apices, in a remarkably thick secondary investment. These 
transverse plates are faintly visible in the only section (imperfect) I have 
been able to prepare for the microscope (PI. XX VIII, figs. 3 and 7), but on the 
weathered surface of a corallite (PI. XXVIII, fig. 5) they are much more 
apparent, and are again seen in a semi-vertical natural section of a portion 
of a wall (IT. XXVIII, fig. 6). The close resemblance of these plates to 
dissepimental tissue cannot be denied, although the tissue generally is scanty. 
It introduces an element of structure unlike that of any other member of the 
genus. 
It is difficult to arrive at the precise mode of growth in T. (?) Murrayi , 
but the corallites would appear to form more or less sub-compound bunches, 
the individual members here and there close enough together to become 
united to one another for some portions of their course by their walls. Some 
of the old calices present a double wall on fractured transverse surfaces, as if 
one corallite had sprung up within the other. It would appear from this 
that we have here true calicinal budding. 
The septal apparatus of T. (?) Murrayi , is strictly on the lines of 
Tryplasma, marginal longitudinal lamellae distall \ r produced into spines. 
The lamellae were very numerous, the spines in the calices densly packed, 
