14 BAHIA — BRAZIL. Feb. 1832. 



short time, generally expelled the air and water with con- 

 siderable force from the branchial apertures and mouth. It 

 could emit, at will, a certain portion of the water ; and it 

 appears, therefore, probable, that this fluid is taken in partly 

 for the sake of regulating its specific gravity. This diodon 

 possessed several means of defence. It could give a severe 

 bite, and could eject water from its mouth to some distance, 

 at the same time it made a curious noise by the movement 

 of its jaws. By the inflation of its body, the papillte, with 

 which the skin is covered, became erect and pointed. But 

 the most curious circumstance was, that it emitted from 

 the skin of its beUy, when handled, a most beautiful car- 

 mine red and fibrous secretion, which stained ivory and paper 

 in so permanent a manner, that the tint is retained with all 

 its brightness to the present day. I am quite ignorant of 

 the nature and use of this secretion. 



March 18th. — We sailed from Bahia. A few days after- 

 wards, when not far distant from the Abrolhos islets, my 

 attention was called to a discoloured appearance in the sea. 

 The whole surface of the water, as it appeared under a weak 

 lens, seemed as if covered by chopped bits of hay, with 

 their ends jagged. One of the larger particles measured .03 

 of an inch in length, and .009 in breadth. Examined more 

 carefully, each is seen to consist of from twenty to sixty 

 cylindrical filaments, which have perfectly rounded extre- 

 mities, and are divided at regular intervals by transverse 

 septa, containing a brownish-green flocculent matter. The 

 filaments must be enveloped in some viscid fluid, for the 

 bundles adhered together without actual contact. I do not 

 know to what family these bodies properly belong, but they 

 have a close general resemblance in structure with the con- 

 iervs^ which grow in every ditch. These simple vegetables, 

 thus constituted for floating in the open ocean, must in 

 certain places exist in countless numbers. The ship passed 

 through several bands of them, one of which was about ten 

 yards wide, and, judging from the mud-like colour of the 



