Aug. 1833. 



SEA-PEN. 



117 



the hardened mud. He adds " The Indians often find enor- 

 mous boas ; which they call Uji^ or water serpents^ in the 

 same lethargic state. To reanimate them^ they must be 

 irritated or wetted with water .^^ 



I will only mention one other animal^ a zoophyte aUied 

 to Virgularia^* a kind of sea-pen. It consists of a thin^ 

 straight^ fleshy stem^ with alternate rows of polypi on each 

 side^ and surrounding an elastic stony axis. It varies in 

 length from eight inches to two feet. The stem at one 

 extremity is truncate, but at the other is terminated by a 

 vermiform fleshy appendage, which is separated into two 

 compartments ; and in these, small, yellow, spherical ova are 

 contained. The stony axis which gives strength to the stem, 

 may be traced at this extremity into a mere vessel filled with 

 granular matter. This undeveloped portion is enclosed in a 

 transparent, elastic, irritable bag, containing a fluid in which 

 a very distinct circulation of particles could be seen. This bag 

 floats in one of the compartments of the fleshy terminal ap- 

 pendage. At low water hundreds of these zoophytes might be 

 seen, projecting like stubble, with the truncate end upwards, 

 a few inches above the surface of the muddy sand. When 

 touched or pulled, they drew themselves in, suddenly and 

 with force, so as nearly or quite to disappear. By this 

 action, the highly elastic axis must be bent at the lower 

 extremity, where it is naturally slightly curved; and I 

 imagine it is by this elasticity that the zoophyte is enabled 

 to rise again through the mud. Each polypus, though 

 closely united to its brethren, has a distinct mouth, body, and 

 tentacula. Of these polypi, in a large specimen, there must be 

 many thousands ; yet we see that they act by one movement ; 

 that they have one central axis connected with a system of 

 obscure circulation ; and that the ova are produced in an 

 organ distinct from the separate individuals. Well may one 

 be allowed to ask, what is an individual ? I will add only one 

 other observation on this zoophyte. The cavities leading 

 from the fleshy compartments of the extremity, were filled 



* I believe Virgularia Patagonica of D'Orbigny. 



