16 



ATLANTIC OCEAN. 



Mar. 1832, 



not extend within the extreme conical points. In some, 

 small but perfect spheres of brownish granular matter sup- 

 plied the place of the septa ; and I observed the curious 

 process by which they were produced. The pulpy matter of 

 the internal coating suddenly grouped itself into lines, some 

 of which assumed a form radiating from a common centre ; 

 it then continued, with an irregular and rapid movement, to 

 contract 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 appearance was as if an elastic mem- 

 brane, for instance a thin Indian-rubber ball, had been 

 distended with air, and then burst, in which case the 

 edges would instantly shrink up and contract towards a 

 point. The formation of the granular sphere was hastened 

 by any accidental injury. I may add, that frequently a 

 pair of these bodies were attached to each other, as repre- 

 sented in the accompanying rude drawing, cone beside 



cone, at that end where the septum occurs. When float- 

 ing uninjured in the sea, the formation of the spherical 

 gemmules perhaps only takes place, when two of the plants 

 (or rather animals, according to Bory St. Vincent) thus 

 become attached, and married to each other. Nevertheless, 

 I certainly witnessed this curious process in several indivi- 

 duals, when separate, and where there was no apparent cause 

 of disturbance. In any case it does not seem probable, from 

 the fixed structure of the septum, that the whole of the 

 granular matter is transferred from one to the other body, as 

 with the true Conjugatee. 



I will here add a few other observations connected with 

 the discoloration of the sea from organic causes. On the 

 coast of Chile, a few leagues north of Concepcion, the Beagle 

 one day passed through great bands of muddy water ; and 



