542 Brazilian Corals and Coral Reefs. [September, 



masses, conforming more or less in size and shape to the projec- 

 tions from which they spring. This law of variation seems to 

 hold good for the entire coast. A small species of Porites occurs 

 at times, associated with the two species above named. 



A little deeper down, where they can seldom, if ever, be uncov- 

 ered by even the lowest tides, come in other and more showy 

 corals. Mussas grow profusely at many localities, seeming to 

 prefer the abrupt outer edges of the submerged rocks. They 

 belong to two species, one with separated cells not now living in 

 the Bay of Bahia, the other having the cells closely joined nearly 

 to their summits. Occasionally we find small heads of Orbicella 

 and Acanthastraea in similar situations, but these more commonly 

 inhabit deeper water. The same may also be said of Millepora, 

 the hydroid coral, of which there are two common and one rare 

 species on the Brazilian coast ; in very shallow water it is stunted 

 in growth and usually bears only short branches. Living on the 

 under sides of stones, in company with encrusting bryozoans, is 

 a very small Astrangian, consisting of many widely separated 

 cells united by thin creeping stolons. 



An Agaricia, very rare in the Bay of Bahia but more common 

 elsewhere, generally grows attached to some other coral, as, for 

 instance, to the dead base of Mussa. On the coast of Pernam- 

 buco there is also a small Stylaster attaching itself in the same 

 way. Pectinia braziliensis is seldom found adhering to a rocky 

 surface, but is very abundant at times in sheltered situations, 

 partly buried in the mud. There remains only a single other 

 Madreporian coral to mention here ; it is the Porites solida, which 

 seems to live nearly everywhere excepting in the Bay of Bahia. 



This closes the list, with one or two exceptions of rare species, 

 of the shallow water Madreporian corals of Brazil. The most of 

 the species enumerated are very widely distributed, ranging along 

 the entire coast north of Cape Frio. But they are not confined 

 to the shore, for the majority also occur on the outer reefs, which 

 are, so far as we know, entirely built up of a few of these same 

 species. From depths ranging from twenty-seven to forty fath- 

 oms were procured several small corals ; but these forms can, at 

 the most, play only a very insignificant part in reef-building. 



Let us return, however, to our studies in the bay. Five or six 

 species of Gorgonians are abundant nearly everywhere, growing 

 as commonly from small stones and dead corals imbedded in the 



