NOTES AND QUERIES. 83 
A good account of the Raphidiophrys is given as an extract from 
Dr. Leidy’s ‘‘Fresh-water Rhizopods,” Mr. Bolton telling his 
readers that he has lately found a fair quantity of these organisms 
near Birmingham. A good account of Hemzdium nasutum may 
be found in Saville Kent’s ‘ Manual of the Infusoria.” This or- 
ganism, together with C/z/omonas spiralis, has been found by Mr. 
Bolton amongst decaying leaves in Sutton Park. He says :— 
“In going yesterday to collect the Hemidinium for despatch 
to-day, I found in the ditch nothing apparent but dry dead 
leaves, but under these in the mud was a little water, which, on 
my return home, proved to contain an abundance of Hemidinium, 
but there is a larger proportion of other larger Infusoria and some 
common Rotifers.” We are glad to learn that Mr. Bolton 
has been awarded a Gold Medal of the International Fisheries 
Exhibition for his exhibit of Invertebrata, and through his kind- 
ness we are enabled to give our readers a copy of the design of 
this medal. 
HuitmME Fretp Natura.ists.—At the last ordinary meeting, 
Mr. Richard Astley read a paper on the Age of Trees. He ex- 
plained the mode of formation of the annual rings, and stated that 
they were but a partial test of age because of the irregularity of 
their arrangement caused principally by heliotropism. He cited 
the case of a specimen now in the Kew Museum which exhibits 
250 distinct rings on one side of the section and some fifty on the 
other. Again, we are met by another difficulty in this method of 
ascertaining age. The rings can only be counted when the tree is 
in its prime, as old trees are frequently hollow or such a deposition 
of lignine has taken place in the tissues as to obliterate the mark- 
ings. The only reliable method is to measure the girth at a given 
height above the ground, comparing the results of a large number 
