SEA-I'EN. 127 



erly aestivation, of animals is determined, not by 

 the temperature, but by the times of drought. Near 

 Rio de J aneiro, I was at first surprised to observe, 

 that, a few days after some little depressions had 

 been filled with water, they were peopled by nu- 

 merous full-grown shells and beetles, which must 

 have been lying dormant. Humboldt has related 

 the strange accident of a hovel having been erect- 

 ed over a spot where a young crocodile lay buried 

 in the hardened mud. He adds, " The Indians 

 often find enormous 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 

 (I believe Virgularia Patagonica), a kind of sea-pen. 

 It consists of a thin, straight, fleshy stem, with al- 

 ternate rows of polypi on each side, and surround- 

 ing an elastic stony axis, varying in length from 

 eight inches to two feet. The stem at one ex- 

 tremity is truncate, but at the other is terminated 

 by a vermiform fleshy appendage. The stony axis 

 which gives strength to the stem may be traced at 

 this extremity into a mere vessel filled with granu- 

 lar matter. At low water hundreds of these zon- 

 phytes 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 suddenly drew themselves in 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 alone that the 

 zoophyte is enabled to rise again through the mud. 

 Each polypus, though closely united to its breth- 

 ren, has a distinct mouth, body, and tentacula. Of 

 these polypi, in a large specimen, there must be 



