REPRODUCTION OF THE SERPUL.E. 31 ? 



the percolation of calcareous matter, and afterwards 

 to have been gradually upheaved, the outer and loose 

 parts during the process having been worn away by 

 the action of the sea, and the solid nucleus left as we 

 now see it. Although night and day the waves of 

 the open Atlantic, turbid with sediment, are driven 

 against the steep outside edges of this wall of stone, 

 yet the oldest pilots know of no tradition of any 

 change in its appearance. This durability is by far the 

 most curious fact in its history ; it is due to a tough 

 layer, a few inches thick, of calcareous matter, wholly 

 formed by the successive growth and death of the 

 small shells of Serpulw, together with some few Bar- 

 nacles, &c. These insignificant organic beings, espe- 

 cially the Serpulse, have done good service to the 

 people of Pernambuco, for without their protective 

 aid the bar of sandstone would inevitably have been 

 long ago worn away, and without the bar there would 

 have been no harbour/ 



Nothing whatever appears to be known relative to 

 the mode of reproduction of these Annelids. I have 

 paid much attention to the subject, but as yet have 

 not gained any positive information regarding it. 

 The only fact which I consider worthy of being 

 chronicled is the following : On one occasion, when 

 quite a novice in Marine Zoology, while observing a 

 beautiful group of Serpulae seated on a stone, I saw 

 issuing from out one of the tubes a kind of very fine 

 dust, of a rich crimson hue, which continued to arise 



