PELAGIC CUM'EKVyK ANU INl'UriuKlA. It) 



remarks, that the sailors gave to this appearance 

 the name of sea-sawdust. 



Near KeeUng Atoll, in the Indian Ocean, I ob- 

 served many little masses of confervas a few inches 

 square, consisting of long cylindrical threads of 

 excessive thinness, so as to be barely visible to the 

 naked eye, mingled with other rather larger bodies, 

 finely conical at both ends. 

 Two of these are shown 

 in the woodcut united to- 

 gether. They vary in length from "04 to "06, and 

 even to -OS of an inch in length ; and in diameter 

 from -006 to -008 of an inch. Near one extremity 

 of the cylindrical part, a green septum, formed of 

 gi-anular matter, and thickest in the middle, may 

 generally be seen. This, I believe, is the bottom 

 of a most delicate, colourless sac, composed of a 

 pulpy substance, which lines the exterior case, but 

 does not extend within the extreme conical points. 

 In some specimens, small but perfect spheres of 

 brownish granular matter supplied the places of the 

 septa ; and I observed the curious process by which 

 they were produced. The pulpy matter of the in- 

 ternal coating suddenly gi'ouped itself into lines, 

 some of which assumed a form radiating from a 

 common centre ; it then continued, with an irregu- 

 lar and rapid movement, to conti'act itself, so that 

 in the course of a second the whole was united into 

 a perfect little sphere, which occupied the position 

 of the septum at one end of the now quite hollow 

 case. The formation of the gi'anular sphere was 

 hastened by any accidental injury. I may add, 

 that frequently a pair of these bodies were attach- 

 ed to each other, as represented above, cone beside 

 cone, at that end where the septum occurs. 



I will here add a few other observations connect- 

 ed with the discoloration of the sea from organic 



