180 ' lAXTHIXID^. 



confirmed the observations of Dr. Coates and Mr. Adams. 

 He had an opportunity in 1862 of examining several 

 living specimens which were blown ashore in the Bay of 

 Bouliff near Calles in Algeria. They were placed in an 

 aquarium, where they commenced to put their damaged 

 floats in repair. The float is formed with tolerable re- 

 gularity_, the cells of which it is composed being poly- 

 gonal, owing to their mutual pressure. The original 

 form of the cells, however, is circular, as may be seen 

 in those on the extremities of the float. . The foot of the 

 animal is di^dded into two distinct parts. The hinder 

 and larger part is flat, and to this the float adheres ; 

 the anterior part is rounded in front, and it is this part 

 which constructs the float. Without the beautiful draw- 

 ings which accompany the paper it will be difficult to 

 give a clear idea of the modus operandi. The anterior 

 part of the foot is extremely flexible, and the animal has 

 tlie power of causing its extremity to assume a cup- 

 shape ; when in this position the foot is laid on the float 

 at the spot where a new cell is to be added, the edges of 

 the foot embrace the float, and the extremity or point is 

 raised up, out of the water, in the cup-shape already 

 mentioned, so as to collect a small portion of aii'. The 

 animal is now seen to move the foot backwards and for- 

 wards, as if to secure the firm attachment to the float 

 of a glutinous film or layer which at the same time 

 exudes from the foot. When the animal removes its 

 foot, this glutinous film has become a cell and remains 

 attached, with its imprisoned air-bubble. M. Lacaze- 

 Duthiers noticed that all the specimens which had lost 

 their floats, although perfectly alive, remained at the 

 bottom of the water, and that some of the more lively 

 crept with the foot, slowly and painfully, up the sides of 

 the vessel, and on reaching the top they turned on their 



