274 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
A species of Agaricia was found growing plentifully in the Mussa 
clusters. The polyps are of a beautiful brownish-red color with green 
centres. 
This whole Maceio region is a very interesting one, and deserves more 
thorough investigation. North of this main reef just described there 
are many smaller patches of coral rock that may contain some of the 
other Brazilian corals described from Bahia and the Abrolhos by Verrill 
and Rathbun. If the collection described in this paper is complete, it is 
a remarkable fact that the range of a number of the corals so common in 
the south should end abruptly in the region of Bahia. 
Rásumá or CONCLUSIONS REGARDING THE CORAL REEFS. 
The coral reefs of Brazil extend along the coast from the Abrolhos 
Islands in south latitude 18° nearly to the mouth of the Amazon River. 
The reefs, however, are not continuous, but are broken by many and 
large gaps. The only reefs well off the coast are on the Rocas Island in 
south latitude 3° 51’, west longitude 33° 48’, and 225 kilometres from 
the mainland. The reefs of the coast are both barrier and fringing reefs. 
They are usually narrow, — from ten to fifty metres in width ; the widest 
are the barrier reefs, some of which are about thirty kilometres in width. 
Most of the near-shore reefs are quite thin, probably not exceeding a 
thickness of ten metres; the reefs that grow further out are thicker, and 
it is possible that some of the barrier reefs, like those of the Abrolhos 
group and of the Cape St. Roque group, have a maximum thickness of a 
hundred metres at their outer edges. 
There were coral reefs on the Brazilian coast during Cretaceous times 
and also during Eocene and Pliocene times. The coral reefs may, there- 
fore, be regarded as having survived since the Pliocene, at least. The 
reef corals are found both beneath and on top of the stone reefs with 
which they are contemporaneous. It is highly probable that some of 
the coral reefs of the coast grow upon and conceal stone reefs. Tho 
coral reefs have no connection with eruptive phenomena, with the pos- 
sible exception of those of the Rocas, which are two hundred and twenty- 
five kilometres from the mainland. 
Many of the Brazilian coral reefs, having reached the upward limit of 
growth, are now dead and are growing only laterally. This is true of 
both the large barrier reefs and of the fringing in-shore reefs. 
The coral polyp fauna of Brazil contains twenty-eight known species. 
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