hill: geology of JAMAICA. 237 



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 cm. 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 Beliastrcea 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 

 costae, which are not distinct on the unworn surfaces. Corallites joined by 

 costse. 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 w^ell developed, the dissepiments are fine and close together. 



Localities. Catadupa, Jamaica (R. T. Hill, collector); Mount Hindmost, 

 District of Clarendon, Parish of Clarendon (Jamaica Institute collection). 



Notes. The results of the study of the type of Reuss's Heliastrcea exsculpta, of 

 the original specimens of Duncan's " H. exsculi^ta" and of the type of Duncan's 

 Heliastrcea cyathiformis^ have already been given in the Introductory remarks.^ 

 Duncan's specimens of " Heliastrcea exsculpta " 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 Heliastrcea 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 Heliastrcea 

 cyathiformis is extremely misleading. 



Additional Localities. Duncan had specimens from Trout Hall, Mount Hind- 

 most, and Cupuis identified as Heliastrcea exsculjota. The specimens from the 

 first two places are without any doubt Multicolumnastrcea 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 Heliastrcea 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. 



