338 Mr. A. H. Foord on 
XXXVIL—On three new Species of Monticuliporoid Corals. 
By Artuur H. Foorp, F.G.S., late Assistant Palaon- 
tologist to the Geological and Natural History Survey of 
Canada. 
[Plate XII.] 
1. Monotrypa macropora, Foord. (Pl. XII. figs. 1-1 d.) 
Corallum discoid, concavo-convex, with expanding and 
gradually tapering margins; attached by the base to some 
foreign body, such as a shell or trilobite. Base covered with 
a thin and concentrically wrinkled epitheca. Cells opening 
upon the upper surface of the corallum. Calicinal surface 
almost smooth, with very slightly raised areas about 5 milli- 
metres apart, occupied by groups of cells a little larger than 
the average. Of the larger cells about one to one and a half 
fill the space of 1 millimetre ; of the smaller about two are 
comprised within the same limits. The largest specimen 
known to the writer measures about 7 centimetres in its 
greatest diameter and about 25 millimetres in thickness, from 
the centre of the surface to the base, measured vertically. 
Microscopic characters.—In sections taken as near to the . 
surface as possible the corallites are observed to be polygonal, 
mostly six-sided, with comparatively thin but remarkably 
clearly outlined walls, the original divisions of which may be 
faintly discerned under a moderately high power. Clusters 
of the larger cells are seen grouped together amongst those of 
the average size, while at rare intervals a few much smaller 
ones are intercalated with the former (fig. 10); but these 
are not of the nature of interstitial tubes, their tabulation not 
differing in any respect from that of the other corallites. Sec- 
tions cut longitudinally to the axis of the corallites show that 
these are furnished with complete horizontal or slightly curved 
and very delicate tabule, which vary from about one half to 
two tube-diameters apart. 
This species may be readily distinguished from the only one 
of the genus hitherto described from British rocks, viz. Mono- 
trypa crenulata, Nicholson *, by its discoidal habit of growth, 
the large size of its corallites, its more abundant tabulex, the 
total absence of crenulations in the tube-walls, and lastly by 
the presence of small angular corallites. 
The writer is indebted to the kindness of Mr. George Maw, 
* Ann. & Mag. Nat. Hist. ser. 5, vol. xiii. p. 124, fig. 2 (1884). 
