NATIONAL FISHERY CONGRESS. 245 



the desired direction. A small piece cut out would not seriously injure the sponge 

 and would show the quality of fiber as well as the entire body. Selected individuals 

 might be removed from the general ground and during the breeding season placed 

 together in large live boxes. The u spat" collected from such individuals would 

 doubtless develop into superior sponges. I do not know any marine animals which 

 would seem to be so adapted to continuous rearing, with constant improvement of 

 breed, as sponges. Their plant-like habit of growth makes it easy to handle and 

 experiment upon them. Their variability, especially in the matter of the skeleton, 

 would seem to insure success to selective breeding; and the very simplicity of what 

 is desired, namely, improvement in the quality of the skeletal fiber, would at once 

 lend a directness to the efforts of the cultivator, which should lead to comparatively 

 early results. 



In closing, I may direct your attention to a method of race improvement, so far 

 practiced only in the cultivation of plants, but to which the vegetative character of 

 sponges will readily lend itself. I refer to the method of grafting. The ease with 

 which two or more individuals of the same species of sponge, irrespective of age, may 

 be made to fuse, and become henceforth a single individual, is well known. Dr. Grant 

 records observations on this head as far back as 1826. Among later experimenters I 

 will only mention Yosmaer. This fusion of individuals goes on commonly in nature. 

 An interesting account of a number of cases may be read in Johnston's British Sponges 

 and Corallines, published 1842, page 11. 



The natural tendency of sponges to grow together, coupled with the ease with 

 which they may be propagated by cuttings, would make artificial grafting in these 

 animals a simple matter. With a small plantation of very superior sponges at hand, 

 the result of careful breeding from selected individuals, and other plantations con- 

 sisting of sponges grown from cuttings, grafting ought to be not only a scientific but an 

 economic success. At slight expense, large numbers of common sponges might be 

 improved simply by pinning to the common cutting a piece of the improved variety. 



CHAPEL HILL, NORTH CAROLINA. 



