and our walk will be the longer. In midsummer the bed is dry, and
almost obliterated by the drift. On the approach of autumnal rains,
the farmers plough a passage for the water, to prevent their lands
from being submerged.

On the east side, masses of conglomerate rock are strewn in wild
confusion. By the action of untold ages the connecting cement is worn
away from between the pebbles, leaving them prominent; and wherever
the attrition of the sea has loosened one from its bed, the hollow has
become the habitation of Mollusca and Algae.

Beyond that ponderous boulder are many dark recesses among the
overlying stones. Strip back your sleeve, thrust in your hand, and
grope carefully about. In this way I once grasped a prickly thing that
startled me. Drawing it to light, it proved to be an Echinus,
Sea-Urchin, or Sea-Egg. That one was not larger than a walnut, was
shaped like a _brioche_, and resembled a chestnut-burr. Its color was
a delicate green, verging to brown.

Much larger living Echini are found on this spot. There is a shell
now, more than two inches in diameter. It is wholly covered with
spines half an inch in length. Radiating from a common centre,
flexible at the base, they stand erect at right angles with the shell
when the Urchin is in health; but in disease or death order is lost,
and they lie across each other in great confusion. Their connection
with the shell is very remarkable, for it is by a ball-and-socket
joint,--the same articulation which gives the human hip its marvellous
liberty of action. Between them are five rows of minute holes, and, in
life, a transparent, hair-like foot is protruded from each, at the
pleasure of the owner. When disposed to change its situation, it