THE BABY SEA-URCHIN. 
81 
rosette. It went on growing for two or three years, 
lengthening the five knobs into pointed rays, and 
became the common Five-Fingered Star-fish. 
No. 4 took a different road from any of the three 
Fig. 34- 
that had gone before him. He 
too had long thin rods in his 
body, all pointing one way, 
so that his body looked like 
a painter's easel, and at the top 
of the easel a number of fine 
plates of lime began to form 
in the shape of a tiny round 
box (b y Fig. 34 A) with prickles 
all over it ; and by and by this 
box sucked up the jelly-body, 
leaving only a thin film over its 
shell, and sinking to the bottom 
a tiny Sea-Urchin, burrowed 
a hole for itself in the sand. 
Lastly, No. 5 did not form 
anything solid within its jelly- 
body, but growing a stomach 
and feet, and other soft parts, Infancy of a Sea-Urchin.* 
stretched itself out into the Miiller - 
shape of a sausage, put out A, The jelly-animal with 
. _ , its lime-rods a a, swimming 
some leaf-like tentacles round abo ut and feeding while the 
its mOUth (B, Fig. 35), and lay- tiny sea-urchin 6, is forming 
i ., r within it. B, The young sea- 
ing down some spikes of U1 . chm> 
lime in its skin, became a 
little worm -like creature with tiny tubes for feet, 
the young of the Sea-Cucumber^ and soon found 
* Echinus. 
t Holothuriadoe. 
