No. 3-] DEVELOPMEN'T OF MARL\E SPONGES. 325 



Collecting and Einbiyological JMctliods. — During August, 

 September, and October, the Tedanias at Green Turtle Cay 

 were found to contain large numbers of embryos which turned 

 out to be gemmules, the development of which is essentially 

 like those of Esperella. The embryos were imbedded in the 

 mesoderm, but though they were abundant, they were not 

 sufficiently so to cause any breaking down of the sponge tissue. 

 The mesoderm of Tedania B. is a bright red and the gemmule 

 embryos which were present in many stages were of the same 

 color. If a Tedania is put in an aquarium, almost at once 

 ciliated larvae begin to be cast out of the oscula. For the 

 purpose of obtaining embryos, I found it was useless to keep 

 the adult sponge more than two or three hours. During that 

 time they throw out a good many embryos, but afterwards 

 scarcely any. By changing the water frequently, large as 

 the adults were, I could keep them alive for many hours, but 

 after the first couple of hours they, like so many other marine 

 animals, lose their irritability, and eject no more embryos. In 

 order to get a great number of embryos it was therefore neces- 

 sary to collect many adults, keeping each of them but a short 

 while. In bringing a large sponge like Tedania B. from the 

 collecting grounds to the laboratory, care should be taken to 

 supply it with an abundance of water, and if it must be lifted 

 out of the water, let the exposure to the air be as short as 

 possible. It will be found well to support the sponge with one 

 hand just below the surface of the water, and with the other 

 dip a bucket beneath it. In this way a sponge may be brought 

 into an aquarium without having been out of the water for a 

 moment. It being a matter of considerable time and labor to 

 bring so many sponges from the collecting grounds to the 

 laboratory in a small sail boat, I tried on a few occasions 

 getting my larvae directly on the grounds. Paddling along the 

 mangroves at the head of "Black Sound," whenever we saw a 

 good sponge, my negro boy or I would fish it up and carefully 

 bring it into one of the two large tubs I kept full of water in 

 the bottom of the boat. When we had pretty well filled one 

 of the tubs, I would wait fifteen minutes and then transfer all 

 the sponges to the other tub, and begin examining the water 



