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POPULAR SCIENCE REVIEW. 
THE ECHINUS, OR SEA-URCHIN. 
By St. GEORGE MIVART, F.R.S. 
[PLATE LXV.] 
T HE Englishman, unacquainted with natural history, who 
for the first time visits Marseilles will, when he wanders 
down to its busy port, most probably have his curiosity awakened 
by baskets full of dark, round, spiny bodies (disclosing deep 
yellow parts within), each about the size of an egg. These are 
the sea-urchins, sea-eggs, or echini , which are largely affected 
by the good folks of Marseilles, and constitute one of the many 
objects of their fish-market which interest, surprise, or disgust 
the northerner on his first arrival on the Mediterranean shore. 
A large specimen of echinus well indeed merits its name of 
sea-urchin, for externally it presents an amazing resemblance 
to a rolled-up hedgehog, or urchin, being covered over with 
spines which in size and general appearance are very singularly 
like those of the last-named animal. 
The resemblance, however, between these two animals is of the 
most superficial character only, and two creatures more really 
distinct could hardly be selected from the whole animal kingdom. 
The sea-urchin presents us with a singular mixture of great 
simplicity of structure united with very great complexity. It 
is indeed an animal formed on a very low type, which, while 
strictly preserving that low type, yet preserves it in a wonder- 
fully ornate condition with a quite prodigious number of com- 
plications and adornments. 
The creature, when deprived of its spines, presents the ap- 
pearance of a spheroidal, melon-shaped body (the so-called 
shell), furnished with two poles (each being provided with an 
aperture), and with lines, like meridians, running from the 
vicinity of one pole nearly to the opposite one. The shell when 
thus stripped is seen to be formed of a multitude of parts, to be 
covered with small rounded prominences, or tubercles, and to 
be perforated by a vast number of minute holes, or foramina. 
