274 Dr Grant on the Structure and 
data to enable us to decide either as to its animal or vegetable 
nature. 
The small, yellow, globular bodies observed by many natura- 
lists in the Spongilla Jriabilis in autumn, are distinctly visible 
to the naked eye, regularly spherical, about the size of grains 
of sand. Linnaeus compares them in size to the seeds of thyme, 
of a bright straw-yellow colour, rough on their external surface, 
yielding a little to pressure, and quite elastic. I have found 
them present, and almost equally abundant in the spongilla in 
September, October, November, December, January, and Feb- 
ruary, but have not yet examined this substance in other months, 
to discover at what season, if ever, they are deficient. They 
are distributed very irregularly, but abound most in the deeper 
parts, where they frequently lie loosely collected in groups of 
about twenty or thirty ; they have no perceptible organic con- 
nection with each other, or with the substance in which they 
are imbedded. I have frequently found a portion of spongilla 
crowded with them, while another growing beside it contained 
none ; and even the same portion sometimes presents them crowd- 
ed in one place, while they are entirely wanting in another. 
They seem to have no proper cell or particular disposition of 
the spieula for their lodgement, but fall out readily when the 
broken substance is moved gently in water ; and there appears 
to be no open passage leading to them from the 'surface, diffe- 
rent from the canals natural to this organized body. When one 
of these round balls is pressed between the forceps, it yields 
with some resistance, bursts suddenly, and a white, semi-opaque, 
viscid matter is forced out. They produce no effervescence 
when thrown into nitric acid, no lime being contained in their 
tough cartilaginous capsules ; the capsules frequently burst af- 
ter remaining a minute or two in this acid, being contracted by 
it, like other horny or cartilaginous substances, before they dis- 
solve. The yellow, elastic capsules, viewed separately through 
the microscope, have a coarse, granular structure, and appear 
studded with transparent points, as if porous, but nothing is 
perceived to escape through them by pressure, till they burst. 
In bursting, I have several times observed the fluid contents 
force out a regular circular portion of the capsule. When 
these yellow globules are exposed for a minute or two to the 
