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HILL: GEOLOGY OF JAMAICA. 
Corallum usually branched; the branches make a very acute angle with one 
another at place of bifurcation, rounded or compressed; the diameter ranges 
from 1 to 3 oem. One compressed branch has a greater diameter of 25 mm., 
and a lesser of 13 mm. The ends of the branches are rounded, some- 
times swollen. An aberrant and unusual form is that of the specimen 
figured by Duncan as the type of Heliastrea cyathiformis. This specimen is 
expanded above and excavated in the central portion so that it has some 
resemblance to a cup. The calices project very slightly or not at all above 
the extra corallite areas. Their diameter is 2 mm., and the distance apart 1 to 
1.5 mm. The extra corallite portion of the corallum densely granulate, the 
granules rounded or elongate and arranged along the summits of flexuous 
costo, which are not distinct on the unworn surfaces, Corallites joined by 
coste. Calicular fossa shallow. The septa are crowded, and the upper margins 
form a little rim that contrasts strongly with surrounding granulate area. There 
are three complete cycles. The first and second cycles are usually indistinguish- 
able in size, both reach far into the corallite cavity and have pali on the inner 
terminations. The margins are slightly dentate. The columella is variable. It 
consists of one, two, three, or four stout pillars, each with a rounded upper sur- 
face. Endotheca well developed, the dissepiments are fine and close together. 
Localities, Catadupa, Jamaica (R. T. Hill, collector); Mount Hindmost, 
District of Olarendon, Parish of Clarendon (Jamaica Institute collection). 
Notes. The results of the study of the type of Reuss’s Heliastrea exsculpta, of 
the original specimens of Duncan’s “ H. exsculpta,” and of the type of Duncan’s 
Helvastrea cyathiformis, have already been given in the Introductory remarks. 
Duncan’s specimens of “ Heliastrea exsoulpta ” are of the same form as Plate 
(so called) are not the species of Reuss at all, but are branches of his own 
XXXVII. Fig. 5 of this paper. His Heliastrea cyathiformis is only an abnor- 
mal form (i. e. it possesses an abnormal shape) of the same thing. The calices, 
etc, are identical in the two. Duncan’s figure of the calices of Heliastrea 
cyathiformis is extremely misleading. 
Additional Localities. Duncan had specimens from Trout Hall, Mount Hind- 
most, and Cupuis identified as Heliastrea exsculpta. The specimens from the 
first two places are without any doubt Multicolumnastrea cyathiformis. The 
specimen from Cupuis is worn, and I could not identify it positively without 
sections, but it seems to be the same species as the other specimens. 
The type of Heliastrwa cyathiformis is from "Trout Hall. 
STIBORIOPSIS, gen. nov. 
Corallum massive, heavy, subplane above, Septa solid, imperforate, dentate, 
pali or paliform lobes before the principal septa, Endothecal dissepiments 
abundant, Wall formed by the fusion of the distal ends of septa. Columella 
1 Vide ante, p. 228. 
