212 AMPHITRITE. 
CHAPTER ex 
AMPHITRITE AND CONGENERA. 
We have already had some examples of the different edifices which 
the instincts of Nature prompt the humbler animals to construct for 
their protection. We have seen the various materials, and the artifice 
employed in the work. It is coarser or finer, more or less durable, 
larger or smaller, but always directed to the same specific purpose. 
In further illustrating the subject, let a few examples be given of 
those eurious and interesting facts, wherein the energies of the humblest 
creatures are aroused, and wherein, at the same time, are disclosed some 
very singular facts in physiology. 
§ 1. AmPHITRITE VENTILABRUM—T7'he Lan Amphitrite—Plate XXX. 
Figs. 1, 2, 3, a 5, 6, iG 8, 9, 10, ible 
At the depth of sixty or seventy feet from the surface of the sea, 
a black leather-like tube, about two feet long, is affixed by the lower ex- 
tremity to some solid foundation. Its position is erect, gradually en- 
larging upwards from a very contracted basis, to nearly the size of the 
little finger, or five lines diameter at the orifice. It frequently resembles 
a reed or vegetable stem of stunted growth, as if furrowed by age, with 
portions of the bark injured below by decay, but fresher and smoother 
above, where visibly more recent and entire. 
