92 NOTES ON 
the same vessel. It first endeavoured to avoid 
the rapid wriggling motion of the latter, fearful 
of getting its antenne entangled with it; but, 
after a few minutes had elapsed, the Nais 
became more quiet, when it seized it by means 
of its monodactyle legs, and devoured it ina 
few seconds, rejecting only the skin. Thesame 
evening I put about a dozen more specimens 
into the same vessel, and in the morning they 
were all devoured; the Molusce it would not 
feed on, though afterwards kept without other 
food. 
They may be preserved alive during the 
winter, and bred in a large vessel of water. The 
eggs are numerous, of an oval figure, and at 
first quite transparent. In a short time the 
rudiments of the future Gammarus are dis- 
cernible near the centre of the egg, which then 
loses its transparency ; they are hatched in the 
spring. 
They usually swim in a curvilinear direction, 
and seldom in a straight line; they are exceed- 
ingly nimble; they often swim in pairs, and are 
said to assist each other in casting their exuvie. 
If well fed, they grow rapidly, measuring half 
an inch in length without the antenne; when, 
however, they are about a quarter of this size, 
