118 Prof. H. A. Nicholson’s Contributions 
racters principally, the method of investigation by means of 
thin sections being of recent origin; and they also gave, as a 
rule, extremely brief descriptions. Hence it is exeeedingly 
difficult, in many cases, among the Monticuliporoids, to be 
certain as to the precise forms to which the older names should 
be attached. In the following notes, therefore, I have not 
employed any of the older specific names, except in cases 
where [ can do so with tolerable certainty of being correct in 
so doing. Those forms which I cannot satisfactorily identify 
with previously described species I have provisionally desig- 
nated by new titles, though it is quite possible that some of 
these will also prove to be referable to species to which 
names have been attached at some earlier date. 
1. Fistulipora crassa, Lonsd. sp. (PI. VII. figs. 1, 1 a, 2, 2a.) 
Heteropora crassa, Lonsdale, Sil. Syst. pl. xv. figs. 14, 14 @ (1889). 
The corallum in this species is ramose, the branches being 
rounded or somewhat compressed, mostly solid, and varying 
in diameter from about one line up to half an inch. The sur- 
face appears to be smooth, and devoid of either monticules or 
macule, so far as I have seen. ‘The tube-mouths are usually 
distinctly, though slightly, elevated above the general surface, 
and are surrounded by a distinct ring, though in some ex- 
ceedingly well-preserved specimens these features are not 
observable. The interstitial tubules may or may not be super- 
ficially recognizable. In thin tangential sections (Pl. VII. 
figs. 1 & 2) the corallites are seen to be oval or circular, not 
markedly pinched in or indented at any point, and varying in 
size in different specimens, being mostly between z}o and 
zy inch in diameter (generally nearer the latter). In one 
section I have examined (fig. 2) two of the corallites are 
seen to be connected by a lateral tube of communication. ‘The 
interspaces between the corallites are rarely more than 74> inch 
in diameter, and they are occupied by interstitial tubuli, which 
are polygonal or angular in shape, with imperfect walls. 
Mostly only a single row of such tubuli separates any pair of 
contiguous corallites, but two rows are also often seen in places. 
In long sections (Pl. VII. figs. 1 a and 2 a) the corallites are 
seen to be crossed by a few complete and approximately hori- 
zontal tabule; while the interspaces between them are occupied 
by vesicular tissue formed by the anastomosis of the tabulee of 
the interstitial tubules. No ‘ spiniform corallites”’ appear 
to be present. 
It is, perhaps, open to question whether Lonsdale’s figure 
and description of Leteropora crassa really apply to this 
