81 JOURNAL OF THE 
though at some convenient depth, and in which the dis- 
charge of larvae may go on normally day after day. 
Such a box must have fine metal gauze windows on the 
sides and above, through which water may pass freely, and — 
yet with meshes sufficiently fine at anv rate to hinder the 
passage of the larvae through them. Projecting shelves, 
which must be easily removable, might be arranged one 
above the other. Thesidesand bottom of the box should, 
moreover, be covered with removable pieces—tiles, for 
instance. The larvae settling down on the removable shel- 
ves or other pieces would attach to them, and might from 
time to time be taken out with as much ease as the 
honey stored up in the modern manutactured comb; 
is removed from the hive. 
The precise form of live-box to be used will naturally 
only be determined after preper experiments. To pre- 
vent as far as possible the settling of the larvae on 
the body of the mother, a phenomenon very apt to occur, 
it will perhaps be found well to place the adult ona per- 
forated tray near the top ot the box, and a series of such 
trays, one above the other, may be found a good device. In 
planning experimental boxes of this sort,the character of 
the motion of the sponge larva should be borne in mirc. 
The larva not only swims,frequently making long,shallow 
dives, but also creeps about over the sides and bottom of 
the vessel in which it is kept. 
The live-box has proved itself of great use to the 
naturalist desirous of obtaining the young stages of 
animals,which are difficult to keep or breed in the labor- 
atory. In this connection I well remember the experience 
of acompaninn (Prof. C. L. Edwards), engaged in the 
study of the development of the large holothurian or sea- 
cucumber (Miilleria), so common in parts of the Bahama 
Islands. It was with the greatest difficulty that a few 
embryos of this form could be got in the laboratory. 
