HILL: GEOLOGY OF JAMAICA. 235 
STYLOCGINIA, Epwarps AND HAIME. 
Styloccenia duerdeni, sp. nov. 
Plate XXXVII. Figs. 1-4. 
1865. Stylocenia emarciata, Duncan (non Lamarck), Quart. Jour. Geol. Soc. Lon» 
don, Vol. XXI. pp. 7, 8, 13. 
1808. Stylocenia emarciata, Duncan, Quart. Jour, Geol. Soc. London, Vol. XXIV. 
p. 23. 
Form of corallum, a convex mass; type specimen, 28 mm. in diameter on 
the base and 24 mm. high. The specimen is broken off from a larger piece, as 
Fig.2, Plate XX XVII. shows; therefore the above measurements do not repre- 
sent the original size of the corallum. Calices shallow, hexagonal, subequal 
in size, 1.5 mm. to 2 mm, in diameter, close together, separated by a simple 
wall which is from a quarter to a half millimeter thick; often there are thick- 
enings at the corners of the calices, and remnants of what appear to have 
been pillars. Septa sixteen, eight large, which fuse to the columella, and 
eight small shorter ones. Dissepiments present, apparently numerous, very 
thin, in places may be close together, .5 mm. apart. The columella is 
styliform. 
Locality. District of St. Mary, Parish of St. Mary, Point Haldane (Institute 
of Jamaica) ; Port Maria (Geological Society of London). 
Type. Collection of Institute of Jamaica. 
The specimen that has come under my observation does not permit a more 
detailed description. The description and figures seem sufficient to make the 
species recognizable. "This is undoubtedly the same as Duncan's Stylocenia 
emarciata, as a comparison of the above description with the notes already 
given on his original speeimen will show. The Stylocenia duerdeni seems to 
me distinct from Stylocania emarciata, both from the descriptions of the latter 
and after a comparison with specimens of the latter in the U. S. National 
Museum. The calices of emarciata are much larger, the maximum diameter 
being 3 mm. The usual diameter is 2.5 mm. or a little more, while in 
duerdeni the usual diameter is between 1.5 and 2 mm., with 2 mm. as a maxi- 
mum. This makes a difference in size of almost a millimeter, Although the 
specimen of duerdeni is worn, in places the surface does not appear to have 
lost much from attrition, so one can determine the depth of the calices. They 
are much shallower than in emarciata, 
MULTICOLUMNASTRZHA, gen. nov. 
This genus is closely related to both Orbicella, Dana, and Columnastrea, 
d'Orbigny. In the description of the only known species of the genus much 
detail is given, 80 here only the more general characters will be pointed out. 
