Orbicella cavernosa. C \ 
(For synonymy see original & 
t j JL _ d? i \ 
d a . » e n ipt^ion.) 
This sped ©a is eo variable that great difficulty hm %mn m*> 
par ieaead in o©»siruet img intelligible dmriftiM* A vary in* 
ieresiing sped wm# obtained fey Prof, Due r dan in J&mai ca and p repent- 
ed toy him to the fniiod state# iational Museum# will fist he da a© ri bed 
in detail a# it ©bow® within itself a wide mags of variation and In* 
;dlcatea th# line© of variation of other specimens more constant in 
their char actors* 
The eor&limm is oblong with the upper surface convex but not uni- 
formly arched or doaod; baa# epithee&t®. Lsagife# 25 m* 5 breadth#. 20 
cm. ; thickness , 11.3 cm. 
Tim specimen has two different hinds of calicos. Th.cs® ©f on® hind 
are rather distant » protuberant# and h&w© subegu&l* not very tall# thick# 
dentate costae. The transverse outline is circular or broadly elliptic 
cal# diameter between thecal summit® 8 mm.; one of the elliptical ©alia®# 
has a greater diameter of 11 mm. » lesser about 9 99 * Th© costa® are 
about 1 mm. taXi f Thcs distance apart# measured between the outer costal 
edges# I® from almost contiguous %& 6 mm* The f re# limb of the coral* 
lit® i@ sub-cylindrical $&d may project between 6 mid 1 mm * The sal* 
ices* as if fbwit by FI. # figs# , are not uniformly distributed# 
and vary in sice, form# and prominence. 
In a fully developed calls® there are 48 septa# ©very other one 
extending to and fusing to ih® columella. All the septa# particularly 
the principals# are rather thick. The margins arc dentate# within 
the calicular cavity they fall abruptly to the bottom of the calicos# 
which are 3 to 4 mm* deep# and then the principal® connect to the cola* 
mella« 
