138 Phylum Porijera 



in a small dish of filtered seawater, and while it is kept closed with the 

 fingers of one hand is repeatedly squeezed between the arms of a small 

 forceps. The pressure and the elastic recoil of the skeleton break up 

 the tissue into its constituent cells and these pass out through the pores 

 of the cloth into the surrounding water. The cells fall to the bottom 

 and may be sown with a pipette on any desirable substratum (slide, 

 cover glass, or oyster shell) immersed in a culture dish of seawater. Or 

 the cells, as pressed out, may be allowed to fall at once on the definitive 

 substratum. The cells attach in the course of an hour or so and the 

 slide or other body may be removed to a fresh dish of water or to a 

 running water aquarium, where it should be raised well above the bottom 

 and protected from the force of the current. Attachment will usually 

 take place by means of coarse reticula which remain permanently at- 

 tached. Reticular pieces if partially freed from the slide will curl up and 

 form balls, the size of which is under control. Such balls may be trans- 

 ferred to slides in other dishes or in running water aquaria. A convenient 

 vessel to use is a porcelain-lined bucket, in which the slides rest on in- 

 verted bottles and are so brought near the surface of the water, the 

 current entering at the bottom. By changing the water two or three times 

 a day, such an arrangement serves in place of a running water aquarium. 

 The balls attach and sponges of desired size may be obtained. The at- 

 tached reticula or balls metamorphose and in the course of a few days 

 will have transformed into incrusting sponges with functional canal 

 systems. Such cultures are easily kept for long periods of time in small 

 wire gauze cages hung in live boxes. Lobular outgrowths and even 

 embryos have developed in sponges treated in this way. 



Modifications in this method of growing sponges have been introduced 

 by J. S. Huxley, K. Miiller, P. Galtsoff, M. E. Faure-Fremiet, M. E. de 

 Laubenfels, J. T. Penney, P. Brien, and others. (See Wilson, 1907 and 

 1911.) 



GROWTH OF SPONGES FROM CILIATED LARVAE 



Mycale (Esperella) fibrexilis has embryos during July-August at 

 Woods Hole, Mass. Larvae are liberated, sometimes at once, on placing 

 the sponge in an ordinary 2 gallon glass aquarium jar. Larvae are 

 picked out with a pipette and transferred to culture dishes where they 

 may be kept by changing the water several times a day. They attach 

 in a day or two. They may be made to attach to cover glasses or if they 

 are to be used as section material it is convenient to coat the dish with a 

 thin layer of paraffin and let them attach to this. Little pieces of paraffin 

 with the attached and metamorphosing larvae may then be cut out, fixed 

 (paraffin and sponge), and hardened, the sponge often detaching itself 

 from the paraffin. 



