62 
Caliees large, equal in size, witt a diameter of |-line, or at times almost 1 line, closely 
set ; calicular edge deeply scalloped. Septa numerous and ■well marked, certainly 
fourteen and sometimes more, irnequal in size. Coenenchyma composed of large and 
well-developed tubes separating the corallites by irregular interspaces, often of small 
extent. A specimen measures 3i by nearly 4 indies. {Nicholson and Etheridge fil.) 
Obs. IL. Eaintreei may be distinguished by the size and contiguity of the large 
corallites, with their strongly scalloped margins. Tho cconenchymal tubuli are irregu- 
larly developed, for between neighbouring calices we occasionally sec only one row of 
tubes, but more commonly the number is increased to two. The latter number varies 
up to three or four, beyoud which we have not observed them to be increased. 
In the contiguity of its calices and frequent diminution of the tubuli, N. Eain- 
treei resembles H. megastoma, McCoy, of the British Silurian rocks, but is at onco 
distinguished by the prominent scalloped edges of the calices, and the flat or little- 
convex form of the corallum. 
In the contiguity of the corallites one to the other there is a good deal of 
resemblance between R. Eaintreei and H. pyriformis, Lonsdale, as figured by Hall 
from American specimens, but the other characters are quite dissimilar. {Nicholson 
and Etheridge Jll.') 
Loc. Broken Eiver, a tributary of the Clarke Elver. {The late B. Eaintree.) 
Helioiites PiiSxiopOKOiDES, Etheridge fil. and Nicholson, PI. 1, figs. 9-11. 
HdioUtcsplasmoporoidcs, Nicholson and Eth. fil., Ann. and Ma^;. Nat. Hist., 1879, iv., p, 25, t. 14, f. 2 a, h. 
1 , „ Nicliolsou, T.<ibulate Corals Tal. Period, 1879, p. 245. 
Sp. Char. Corallum irregularly ovate ; upper surface convex. Calices circular, 
with a thin thread-like margin, average diameter IJ lino, contiguous, but separated from 
one another by small interspaces of coenenchymal tubuli. The latter are large and of 
very irregular form ; some arc elongate with one axis much longer than the other, others 
are polygonal ; and, agai)i, others are without definite outline. Between contiguous 
corallites there is usually but one row of Large oblong interstitial tubes, reaching from 
calice to calice ; or, where the corallites become a little separated from one another, 
these may be increased in Jiumber. Septa almost obsolete, thread-like. A specimen 
measures 5 inches by 4. {Nicholson and Etheridge Jil.) 
Obs. The form and arrangement of the coenenchymal tubidi render the present 
species a very interesting one. If horizontal sections in the mass are examined only 
with the naked eye or ordinary lens, the species will be pronounced a Plasmopora ; and 
this it at first appeared to us to be. It has all the general appearance of this genus, 
especially in the fact that there is often hut a single row of oblong interstitial tubes 
between every two corallites. In such sections the walls of these tubes have quite the 
appearance of thread-like cost® radiating from corallitc to corallite, or bifurcating at 
various angles where their number is increased between the corallites, as in Plasmopora. 
When, however, vertical microscopic sections are examined, the true affinities of this 
peculiar coral at once become apparent. In the first place, the arched and vesicular 
tabula; of Plasmopora are wanting, and we find in their place the straight horizontal 
diaphragms of Reliolites. Secondly, in similar sections the interstitial or ecenenehymal 
structure is found not to consist of vertical canaliculi formed by tho irrcn-ularly 
developed nails of the tubuli, and subdivided by horizontal or convex dissepiments into 
irregularly formed cells as in Plasmopora, but of a series of small, regular, and well- 
developed cells formed by tho iutor.section of the vertical tubuli and their horizontal 
tabulae, which are usually placed on tho same level and correspond with one another, 
precisely as seen in vertical sections of Reliolites megastoma, McCoy. 
