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 “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 Vosmaer. 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. 
