DEVELOPMENT OF SPONGES FROM DISSOCIATED TISSUE CELLS. 7 



tissue to the substratum is so firm that the object (slide or shell) may be removed to 

 an out-of-door live box. 



The form of hve box I have used has a wooden frame 3 feet by 2 feet by 18 inches. 

 The sides, top, and bottom are all made of coarse galvanized-wire netting. There is a 

 door of some size in the top. Round the edge of the box there is a wide strip of wood 

 which projects like a shelf and serves to keep the box floating. After a trial of several 

 places I have found that the best situation in which to keep such boxes is under a wharf 

 where the sponges are somewhat protected from the sun, and where the current is fairly 

 strong and the water therefore clean. In the live box are some crossbars of wood. 

 To these are attached the small galvanized-wire boxes in which are put the objects 

 coated with the sponge tissue. The latter boxes afford an additional protection to 

 the growing sponges. They are especially useful for slides. vShells may have a hole 

 bored through them with a drill and be suspended directly by wires from the crossbars. 

 If the small box is to be made for slides, it will be found convenient to proceed as follows: 



Take a rectangular piece of galvanized-wire netting and fold the edges up, thus 

 making a long, shallow box wide enough for an ordinary sUde. Prepare a piece to serve 

 as the top. Immerse the box and tie the slides to the bottom. The slides should be 

 exposed to the air as httle as possible. After the top has been tied on, the boxes, each 

 with a number of sHdes, are suspended from the crossbars in the live box. The slides 

 may be removed, if it is desired, from day to day and examined under the microscope 

 in a glass dish of water. Thus the gradual transformation of Llie coating of sponge 

 tissue into a functional sponge may be followed. 



In the course of a week it will be found that the slide is covered with a thin incrusting 

 sponge provided with pores, oscula, canals, and flagellated chambers. If slides or 

 shells on which sponges have been started in this way are kept suspended in the live 

 box for one to two months, they grow thicker and develop the characteristic species 

 skeleton. Sponges were grown very successfully in this way during the past summer 

 by my assistant, Mr. R. R. Bridgers. Among the hundred or so sponges which survived 

 accidents during two months many had at the end of that time developed reproductive 

 bodies (egg or asexual embryos?) and several had developed lobular outgrowths Uke 

 those of the specimen shown in figure 2. 



As already stated, for the purposes of obser\'ation it is best to scatter the tissue 

 sparsely over covers or slides. And these may be kept in laboratory dishes or aquaria. 

 Differentiation goes on at a decidedly slower rate than in preparations placed in the 

 live box. 



Some stages in the later history of the conglomerate masses first formed (such as 

 that shown in fig. 24) are shown in figures 3, 4, and 6 of plate i. The conglomerate masses 

 exhibit amoeboid changes of shape and throw out pseudopodia all over the surface. 

 Many of the pseudopodia are fine, filose processes, others bleb-like, while others are 

 processes of some size, covered themselves with delicate small pseudopodia. Neigh- 

 boring masses fuse together. The resultant masses may be rounded or irregular or have 

 the character of networks. Figure 3 is a photograph of a cover-glass preparation. The 



