MOTOR REACTIONS OF THE FRESH-WATER SPONGE. 1 65 



by the fact that the chimney did not contract or in any way 

 change its shape. 



Subjecting the sponge to a low temperature does not have as 

 disastrous an effect as increasing the temperature. Between 20 

 amd 30 C. seems to be approximately the temperature at which 

 it thrives best. It is unable to live at a temperature of 40 C. 



The oscular chimneys being continuous with the dermal 

 membranes and themselves being contractile, one would expect 

 to find the dermal membrane also contractile. It is capable of 

 contraction to a slight extent under certain conditions. The 

 chief contractile fibers, however, seem to be found only in the 

 sphincters of the chimneys, which probably work against the 

 general pressure of the water going out through the chimney. 



Although in most cases, the responses of the fresh-water 

 sponge were similar to the responses of Stylotella, there is one 

 noticeable difference. This sponge responds to stimuli much 

 more slowly, and the rate of transmission, where any at all is 

 observable, is much slower. 



BIBLIOGRAPHY 

 Annandale, N. 



'11 Note on the Fresh- water Sponge, Ephydalia japonica and its Allies. Proc. 

 U. S. Nat. Museum, Vol. 38, pp. 649-650. 

 Balfour, F. M. 



'79 On the Morphology and Systematic Position of Spongida. Quart. Jour, 

 of Micr. Sci., Vol. 19, pp. 103-109. 

 Delage & Herouard. 



'oo Zoologie Concrete (2), 1 Partie. 

 Evans, Richard. 



'99 The Structure and Metamorphosis of the Larva of Spongilla lacustris. 

 Quart. Jour. Micr. Sci., new series, Vol. 42, pp. 363-463. 

 Grant, R. E. 



'23 Observations on the Structure and Functions of the Sponge. Edinburgh 

 Philos. Jour., Vol. 13, pp. 94-107, 333-34°; Vol. 14, pp. 113-124, 336-341 • 

 Ed. New Philos. Jour., Vol. 2, pp. 121-141. 

 Jaffe, E. 



'12a Bemerkungen uber die Gemmulae von Spongilla lacustris L. und Ephydatia 



fluviatilis L. Zoologischer Anzeiger, Vol. 39, pp. 657-667. 

 '12b Die Entwicklung von Spongilla lacustris L. und Ephydatia fluviatilis L. 

 aus die Gemmula. Zoologischer Anzeiger, Vol. 39, pp. 705-719. 

 Minchin, E. A. 



'00 Sponges. Lankester's Treatise on Zoology, p. 44. 



