SPONGILLA. 161 



short, compressed lobes, sharp ridges, thhi laminae, or cylmdri- 

 cal small branches rounded at their extremities, and it presents 

 numerous very distinct apertures, of different sizes, leading into 

 its interior. From the looseness of its porous surface and inter- 

 nal texture, and from its mode of enveloping substances in the 

 progress of its growth, we generally find in its interior portions 

 of sand, mud, or gravel, shells of fresh water testacea, frag- 

 ments of roots or branches of trees, tubularige, larvae, particu- 

 larly of phryganeae, innumerable animalcules, and different kinds 

 of ova. 



" In its living state, the Sp. friabilis is so soft and brittle that 

 it can scarcely be handled or lifted without tearing, feels slight- 

 ly unctuous between the fingers, has a strong disagreeable smell, 

 like that of stagnant ditches in the heat of summer, tastes cool- 

 ing without any marked flavour, and quickly diffuses among the 

 saliva, leaving only some earthy particles between the teeth ; 

 it sinks slowly in water, appearing lighter than most marine 

 sponges. When pressed, a thin slimy turbid greenish-coloured 

 matter escapes, mixed with a considerable portion of water, and 

 the remaining fibrous portion has a light grey colour, and stiff 

 gritty feel. When allowed to putrefy in water, a thick, fatty 

 layer covers the surface of the fluid, the water acquires a tur- 

 bid yellowish colour, the Spongilla becomes of a blackish-green 

 hue, and emits a most offensive putrid animal odour, like that of 

 the most putrid offals. A portion of it, whether fresh or putrid, 

 placed on a red hot iron, smells like burning skin or membrane, 

 the soft parts are dissipated, and the fibrous residue becomes 

 red hot, but does not consume nor change much its form." Grant. 

 To this excellent description of the Spongilla by Dr Grant, I 

 have only to add that, when growing in running water, it fre- 

 quently assumes an arborescent form, rising to the height of 

 from six to twelve inches and dividing, like a leafless shrub, into 

 cylindrical tapered branches, which are often loaded with the 



