234 BULLETIN : MUSEUM OF COMPARATIVE ZOOLOGY. 



matter formed by lime-secreting animals of diflferent kinds is here 

 harder than it is near the upper end of the reef, though one may 

 sometimes bi'eak through and sink to his armpits, or even over his head 

 without touching bottom. It is here that the course of the barrier is 

 more broken into zigzags. 



The Barreta da On9a, about the middle of the reef, is ten or fifteen 

 metres in width, and allows the heavy swell from the ocean to pass 

 through. This entrance is deep, and along its bottom grow several 

 large MiUepores, which could not be collected on account of the depth 

 and roughness of the water. Xear the south end, and on the inside of 

 the reef, there are a few pools containing a number of corals of different 

 kinds. Ko Mussas were found on any part of the Parahyba reef. 

 With the exception of the absence of 3Iussa Tiaiitii and the presence of 

 Eunicea sulphurea, the fauna of this reef seems to be about the same as 

 that of Maria Farinha on the Pernambuco coast. The marked absence 

 of living corals from the northern part of the reef is probably due to 

 some extent to the fact that they have been and still are taken out by 

 the inhabitants livmg in the neighboring villages for the purpose of 

 making lime. This burning of the corals for lime must be a very old 

 custom, and the amount of coral rock thus used must have been at 

 times very great. The Fortaleza da Barra at the mouth of the river, 

 built in 1712 on the Ponta da Balea, has pieces of imperfectly calcined 

 coral in the mortar, and it is plastered in places with lime made from the 

 corals of this convenient reef. The city of Parahyba gets its supply of 

 lime from the same source, and the burning is still carried on. The 

 result is that there are no large coral heads to be found much short of 

 the southern extremity of the reef. Here, however, are some very rich 

 pools a hundred metres or so within the barrier edge of the reef filled 

 with Eunicea, Pontes, Facia, PlexaureUa, and Millepora. The ]:)art of 

 reef facing tlie "waves of the open sea also abounds in coralhnes, sea- 

 weeds, crustaceans, etc., and tlie cavernous calcareous pieces below look 

 like fairy grottos as the retreating waves leave the Bryozoa and delicate 

 Algae dripping with water. The channel between the coral reef and the 

 land admits of barcaqas, Avhich may pass in and out at the Barreta do 

 P090. At low tide, however, only the smallest barca^as can pass readily. 

 At this last-mentioned barreta the end of the northern reef lies outside 

 of the northern end of the reef to the south, and the ocean current 

 brings in through this little opening large quantities of seaweed which 

 pile up on the south side of one or two of the curaes ^ nearest the 



^ Cural is the name given the fish-traps made of poles driven into the mud or 

 sand at the bottom of the water. The plural is curaes. 



