Mar. 1832. 



PELAGIC 



CONFERVA. 



15 



water^ at least two and a half miles long. In almost every 

 long voyage some account is given of these confervee. They 

 appear especially common in the sea near Australia. Off 

 Cape Leeuwin^ I found some very similar to those above 

 described they differed chiefly in the bundles being rather 

 smaller^ and being composed of fewer filaments. Captain 

 Cook^ in his third voyage^ remarks^ that the sailors gave to 

 this appearance the name of sea- sawdust. 



I may here mention that during two days preceding our 

 arrival at the Keeling Islands in the Indian Ocean^ I saw in 

 many parts masses of flocculent matter^ of a brownish-green 

 colour, floating in the sea. They varied in size, from half to 

 to three or four inches square ; and were quite irregular in 

 figure. In an opake vessel they could barely be distin- 

 guished, but in a glass one they were clearly visible. Under 

 the microscope the flocculent matter was seen to consist of two 

 kinds of confervcC, between which I am quite ignorant whe- 

 ther there exists any connexion. Minute cylindrical bodies, 

 conical at each extremity, are involved in vast numbers, in 

 a mass of fine threads. These threads have a diameter of 

 about -j-^-Q of an inch ; they possess an internal lining, and 

 are divided at irregular and very wide intervals by transverse 

 septa. Their length is so great, that I could never with cer- 

 tainty ascertain the form of the uninjured extremity ; they 

 are all curvilinear, and resemble in mass a handful of hair, 

 coiled up and squeezed together. In the midst of these 

 threads, and probably connected by some viscid fluid, the 

 other kind, or the cylindrical transparent bodies, float in 

 great numbers. These have their two extremities terminated 

 by cones, produced into the finest points : their diameter is 

 tolerably constant between .003 and .008 of an inch ; but 

 their length varies considerably from .04 to .06, and even 

 sometimes to .08. Near one extremity of the cylindrical 

 part, a green septum, formed of granular matter, and thickest 

 in the middle, may generally be seen. This, I believe, is 

 the bottom of a most delicate, colourless sack, composed of 

 a pulpy substance, which lines the exterior case, but does 



