258 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
structures of greater interest in these waters. Corals grow over the bottom 
in small patches in the open sea, and, without spreading much, often rise to a 
height of forty to fifty or more feet, like towers, and sometimes attain the 
level of low water, forming what are called on the Brazilian coast chapeirões. 
At the top these are usually very irregular, and sometimes spread out like 
mushrooms, or, as the fishermen say, like umbrellas. Some of these chapeiröes 
are only a few feet in diameter. A few miles to the eastward of the Abrolhos 
is an area with a length of nine to ten, and in some places a breadth of four 
miles, over which these structures grow very abundantly, forming the well- 
known Parcel dos Abrolhos, on which so many vessels have been wrecked. 
“T visited in my launch the northwestern part of this reef, where the 
chapeiröes were sufficiently scattered to allow me to sail about among them. 
“ Among these chapeiróes I measured а depth of sixteen to twenty metres, 
and once, while becalmed, I found twenty metres alongside one chapeiräo and 
three metres on top. The chapeiröes, as a general thing, are rarely ever laid 
bare by the tide. They are here, as elsewhere, of all heights and dimensions ; 
but in no case do they reach low-water level, nor according to the testimony of 
the fishermen and whalers, are they ever in any part uncovered. They do 
not coalesce here to form large reefs as they do to the west of the islands. 
When the weather is clear and cloudless, and the water calm, these chapeiröes 
can be readily distinguished at a considerable distance. The surface of the sea 
appears to be flecked by shadows from a sky full of scattered cloudlets, pro- 
ducing a striking effect. The water, being shallow and clear, and with a 
sandy bottom, is of a very light greenish tinge, like that of the Niagara River 
at Buffalo. The general color of the chapeiröes is brown, from their being 
encrusted with patches of Palythoa, and their position is marked by brownish 
spots on the surface of the sea. In the daytime a launch may sail in safety 
among them in calm weather, and a small vessel may traverse some of the 
chapeiräo grounds without danger, but large ships are likely to find themselves 
in a labyrinth from which escape is not easy. In windy weather the waves 
break over the chapeiröes, but if there are white caps beside, and a cloudy sky, 
their position cannot be made out, and it is safest to keep well away from 
them.” 
The corals collected on these reefs by Hartt are described by Verrill.' 
The list is given below. 
List or CORALS COLLECTED BY С, Е. Навтт ON THE Аввогиов REEFS. 
Crass, POLYPL, 
ORDER, MADREPORARIA. 
Agaricia agaricites ? M. Edw. and Haime. 
Siderastraca stellata Verrill, var. conferta Verrill. 
1 A. E. Verrill. Notice of the corals and echinoderms collected by Prof. C. F. 
Hartt, at the Abrolhos reefs. . . . Trans. Conn. Acad. Arts Sci., 1868, I., p. 961-304, 
ELLY. 
