1194 Recent Literature. [December, 
a brittle-star when proceeding along a solid horizontal surface 
(Fig. 7), All echinoderms when placed on their backs can right 
themselves, but different types have different ways of accom- 
plishing this. The common star-fish does this by means of its 
< Fic. 6,—Natural movements of a star-fish on reaching the surface of water. 
suckers (Fig. 8) in half a minute. 
The Astropecten rights itself 
in the way here figured (Fig. 9). 
It stands on the tips of four of 
its rays, while the fifth one is thrown upwards and over the others, 
in order to carry with it the two adjacent rays, “and so eventu- 
ally to overbalance the system round the fulcrum supplied by the 
A 
d 
Sa, 
-a 
S 
t 
é 
sss.” 
*, 
See 
be Sunat 
ee 
Tren, 
Fic, 7.—Natural movements of a brittle-star when proceeding along a solid hori- 
seas r zontal surface. 
of the other two rays, and thus bring the animal down upon 
i Ns a d : fi e7 ë 
ovements are more difficult to perform in the sea- 
orous specimens can right them- 
