3o8 



THE GARDENERS' MONTHLY 



[October, 



cious character; that is, their skeleton structure or 

 frame-work does not consist, as in the familiar 

 marine sponges of commerce, of an elastic net- 



of light received. The slimy growth of Convervae 

 occasionally seen upon the bottom of pools and 

 streams, or dense masses of water-moss, may mo- 



work of tough fibres — but of lines of fasciculated | mentarily mislead the collector; but a pocket lens 



flint-needles, about one one-hundreth of an inch in 

 length, so arranged as to form a loose intertexture, 

 penetrated by canals, and supporting the sponge- 

 flesh. When crushed, therefore, this texture is 

 permanently destroyed and will not resume its 





I® - 



Explanation of Cut. 



The accompanying figures are drawn from nature by the aid of the camera lucida and 

 represent the relative sizes and shapes of lilis parts of several sponges, 'i'he statosphere 

 is magnified about 35 times, the spicules of the skeletcm, marked «, 150 times, all other 

 figures 225 times. 1. Carterius tenospernia— Section of statosphere. (In the other genera 

 these are without tendrils.) 6, dermal or flesh spicule ; (/, birotulate spicule of outer coat 

 of the statosphere. 2. Farmula Batesii— «, skeleton spicule ; '/, parmulitorm spicule of 

 statosphere. 3. Spongilla moutana—n, skeleton spicule. 4. Meyenia fluviatilis— a, skel. 

 spicule; rf, biroiulate stac. spic. and disk of rotule. 5. Tubella Peiiusylvanica— a, skel. 

 spic. : (/, inequibirotulate spic. of statosphere and disk. 6. Meyenia Leidii— a, skel. 

 spic. ; ii, birotulate siat. spic. and disk. 7. Uruguaya cora lioides-o, skel. spic. 

 8. Spongaialacustroides-6, dermal spic. ; c. stat. spic. 9. Spoiigilla fragilis, var. minuta 

 c, Stat. spic. 10. Spoiigilla fragilis, var. calnmeti— o, stat. si)ic. 11. Meyenia crateri- 

 forraa-ri, birot. stat. spi(\ 12. .Meyenia Everetti— d, birot. stat. spic. 13. Heteromeyenia 

 argyrosperma— e, lomj,/, short, birot. stat. spic. 14. Heteromeyenia Kyderi— e, long; 

 /, short; birot. stat. spic. 



will reveal to him at a glance the minute leaves of 

 the moss, or the delicate green threads of the algfe; 

 while in the true sponge he will hardly fail to see 

 the characteristic pores penetrating its surface and 

 to detect the fine points of numerous projecting 

 7/^ spicules. 



The particular feature 

 distinguishing fresh- 

 water from marine 

 sponges is the presence 

 in the former, when ma- 

 ture, of the reproduc- 

 tive bodies known as 

 statoblasts or stato- 

 spheres. These are 

 nearly spherical, light 

 or dark brown, gener- 

 ally easily visible by 

 the naked eye, and oc- 

 cupy positions at the 

 lower surface or 

 throughout the mass of 

 the sponge. They 

 should be carefully 

 looked for and gathered 

 with the specimen, as it 

 is upon the form of the 

 spicules encrusting their 

 surface, that the classi- 

 fication of fresh-water 

 sponges principally de- 

 pends. Either very 

 early or very late in the 

 season minute groups 



original shape. The sponge-flesh, so called, is a of these statospheres may often be found, unac- 

 thin sl\pie covering the spicules and lining the ' companied by the skeleton spicules and slime-like 

 canals of the living organism having a peculiar I flesh of the sponge, and it is well worth while to 

 and not unpleasant odor, when fresh, but betray- gather and preserve them. 



ing its animal nature by an extreinity of foulness These sponges are found growing upon any sup- 

 when the dead sponge has been kept a few days in porting substance except mud, and at every depth 

 ■^^^ater. i beneath the surface of the water; but they afifect 



Many of the species, native in this country, ap- ; chiefly the under and upper surface of stones and 

 pear as mere incrustations of varying size and i timbers, the sides of piling, and of submerged 

 shape, and are froin less than a line to an inch or stumps and branches. The stems and roots of 

 more in thickness. Their surface, smooth, or more or : water plants are often coated and matted to- 

 less tuberculated, is, in some species, supplemented , gether by them. As the silting of earthy matter 

 by a higher growth of branches or finger-like pro- into their pores would soon suffocate them, we find 

 cesses, frequently several inches in length. In in standing pools the most flourishing specimens 

 color they vary from nearly white to the most attached to the under side of stones or water- 

 vivid green, in an almost exact ratio to the degree logged timbers, which shield them from the intru- 



