274 THE ESSEX NATURALIST.
It would be interesting to know whether any direct observations
have been made which bear upon this question."
Since the publication of the above-mentioned letter in Nature
some further interesting evidence has been collected. In the
first place, a portion of a mass of "pwdre ser," found during
the Essex Field Club's "fungus foray" in Epping Forest on
October 16, has come into the writer's hands, and it affords
additional and very convincing evidence of the origin of the
material. Although to the naked eye little but the jelly was
present, some faintly brownish patches of material among it
proved, on microscopic examination, to possess the structure
recognized as characteristic of the walls of the oviducts of Anura.
But what was still more interesting was the fact that attached
to one such patch of tissue, selected at random, a Nematode
worm was found, which it was not difficult to recognize as an
adult female specimen of Oswaldocruzia filiformis (more generally
known as Strongylus auricularis), one of the common parasites
of the intestine of frogs and toads. The presence of this worm
seems capable of explanation only on the assumption that it
had come from the alimentary canal of the same animal whose
oviducts had given rise to the mass of jelly.
More recently still, my colleague, Mr. Parker, has received
from a correspondent in Suffolk some specimens of the jelly
found on the bank of the river Stour. One of these specimens
included the skull, vertebral column and various other bones
of a frog. In this case the frog may actually have been
swallowed by some predaceous creature, and its partly-digested
remains disgorged. In other instances the skull and other
bones were present, but the oviducts had not yet formed a
jelly. Mr. Sawyer, the collector, states that both herons and
otters are present in the locality, besides other possible enemies
of frogs.
Mr. Parker and I have confirmed Melsheimer's experiments,
by soaking the oviducts of a freshly-killed frog in water. We
found that after a very short time the oviduct began to swell,
while in about two hours the expansion of the jelly within it had
begun to split the walls. After being left in water for about 48
hours, the oviduct was no longer recognizable as such, but had
assumed the appearance of a typical mass of "pwdre ser." On
microscopical examination of suitable portions of the mass,