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Some Phenomena in Sponges 
171 
removed. Possibly this might be accomplished by cutting- a 
flattened sheet composed of some hundred larvae (such as I 
have produced) into pieces and inducing- the pieces to meta- 
morphose separately. 
I may now describe some of the details in this process of 
larva-fusion. In a species of Lissodendoryx used the larva is 
of the following- character. It has the usual ovoidal shape 
with a protuberant non-ciliated pole. The anterior pole is 
somewhat truncated and is sparsely ciliated. The rest of the 
body bears the usual thick covering- of cilia. As seen with 
1 reflected light the bulk of the body is dead white, the poster- 
ior pole deep blue, and the anterior pole bluish. This color- 
ation is not absolutely fixed for the species, but the larvae used 
, in my coalescence experiments were all of this character. 
Within twenty-four hours after liberation the ciliated larvae 
are creeping (remaining in contact with the bottom as they 
swim) over the bottom of the dish. Some are now put in 
deep round watch glasses and with pipette and needle coaxed 
together into a clump. Fusion soon begins and on the next 
day plenty of composite larvae are present. The larvae fuse 
endwise, for the most part in pairs. The compound larva so 
produced owing to its weight has a very feeble locomotory 
power. Using pairs that are nearly motionless, larvae may 
be brought together (coaxed with needle) and arranged in a 
desired position on a cover glass for instance. In successful 
1 cases fusion results before the separate masses move apart. 
In this way, selecting an instance, I have added to one arm 
of a quadruple mass a pair of larvae, and to the opposite arm 
two pairs, 
For the purpose of bringing about the fusion of many lar- 
vae the following simple method is convenient. Suppose 
that we have the larvae in a paraffine-coated dish, and they 
are in a late “creeping” stage. Small excavations, 2-3 mm. 
deep and 4-5 mm. wide, are now made in the paraffine, and 
with the pipette the larvae are driven into the holes. They 
lie here in numbers up to and over one hundred, crowded 
;j together and heaped upon one another. Fusion begins soon 
