Corals and coral islands.

GEOfRAPHICAL DISTRIBUTION OF CORALS.

113

cies in deep water, and none of the Pavonise among the comr
pound species; but the massive Siderine (Siderastroeae) are
common, and the foliaceous Agaricive and Mycedia. Of the
Oculina tribe, species of Oculina, Cladocora and Astrangia are
relatively more numerous than in the central Pacific; but
there are none of the Pocilliporids, which are common both in
the torrid and subtorrid regions of the Pacific. Millepores are
very common. Gorgoniae, are of many species.
Prof. Verrill observes that not a single West Indian coral
occurs on the Panama coast, although, on the opposite coast, at
Aspinwall, there are found nearly all the reef-building species
of. Florida, viz.: Porites astreoides Lmk., P. clavaria Lmk.,
Madrepora palmata L., M. cervicornis L., M. prolifera L.,
ilfceandrina clivosa V., M. labyrinthica, M. sinuosa Les., with
other species of Maeandrina, Manicina areolata Ehr., Siderastrcea (Siderina) radiata V., S. galaxea BL., Agaricia agaricites, Orbicella cavernosa V., 0. annularis D. Moreover no
West Indian species is known to be identical with any froln
the Pacifi.: or Indian ocean.
The reefs of the Brazilian coast south of Cape Roque lie in
the subtorlid region of oceanic temperature, or between the isocrymes o1 740 and 68Q. The reef corals extend as far south
as Cape Frio, according to Prot: C. F. Hartt. The species, as
determined by Prof. Verrill, from Prof: Hartt's collections, resemnble the West Indian. All species of Madrepora, Meandrina, Diploria, Manicina, Oculina, genera eminently characteristic of the West Indies, appear to be wanting, while the
most important reef-making genera are Favia, Acanthastreoa,
Orbicella, Siderastrcea, Porite.s, and Mlillepora, and also, of
less importance, MAussa and some others. A few species, viz.:
Siderastrcea stellata V., Orbicella aperta V., Astrcea gravida
V., and Porites solida V., are very close to West Indian spe8