ERA 
laying before him the opinion of the ingenious 
Swammerdarrij who informs us, that^ they arc im- 
pregnated, in the manner of filh-fpawn, by the males, 
after being eje6led by the females. But, befides 
that this doftrine is exploded ~^^en from the hif- 
tory of fillies, it is certain that the males have not 
time to perform this operation, as tlie eggs drop to 
the bottom the inflant they fall into the water. 
Reaumur, who is of a contrary opinion, admits 
that they copulate; but fays, that the aft bears a 
proportion in fhortnefs to the fmall duration of 
their lives; and confequcntly mufl be fo quickly 
accompliihed, as to be fcarcely perceptible. This, 
however, is at beft but fportinga theory; and it is 
probable, that as many infefts are known to breed 
without any impregnation from the males, fo the 
Ephemera m?y probably be of the number. But 
though this branch of natural hifbory is ftill unau- 
thenticatcd, certain it is that, of all infe£ls, this ap- 
pears to be the mofl prolific. As it flutters on the 
fuperficies of the water, two cluflers may be ob- 
ferved to ifTue fi'om the extremity of it's body, 
each containing about three hundred and fifty 
esffs. Indeed, it would Icem as if there was a 
neceflity for fuch a fupply, as, in their reptile flate, 
thefe infe£ts conilitute the favourite aliment of 
every kind of frefla-water fiili. In vain do thefe 
animalcules form retreats at the bottoms of rivers, 
from which they feldom remove; various kinds of 
filh conftantly difturb their repofe, and thin their 
numbers. For this reafon fifhermen diligently 
coUeft a fufficient quantity of thefe infefts, as 
proving the moft grateful bait; and thus turn the 
rapacity of the fifh to their own deftiu£lion. 
Though the fliort fpan of life prefcribed to the 
generality of thefe little animals does not exceed 
two or three hours, there are fome fpecies which 
€xifl for feveral days; and one in particular, after 
quitting the water, has a fecond flough to cafl : 
thefe are often traced in the fields and woods at a 
confiderable diflance from that element, though 
they are more frequently obferved in it's vicinity. 
They are alfo at times found adhering to walls and 
trees, frequently with their heads downward, with- 
out either changing their fituations or pofTefTing 
the linalleft vifible motion. In this condition they 
wait for the miOment of their liberation from the 
laft furrounding incumbrance; and, having at lafl 
attained to a flate of perfeftion, fpeedily die. 
For a particular deicription of fome of the moft 
curious Ephemera, fee Day-Fly. 
EPOPS. A name given by fome ancient writ- 
ers to tlie bird called by modern ones upupa; in 
Englifli, tlie hoopoe. See Hoopoe. 
EPTACTIS. An appellation fometimes given 
to a fpecies of ftar-^fifli of the afbrophyte kind, 
whofe rays or branches, on their firfl projecftion 
from the body, are only feven in number, but which 
in time diverge into many more. 
EQUUS. The claffical name of the horfe. 
See Horse. 
EQUUS MARINUS. An appellation given 
by fome naturalifls to an animal very different 
from the hippopotamus or river-horfe, and more 
ufually known under that of the morfe. 
ERANDGAAS. A fowl of the goofe kind, 
noticed by ibme authors, and by them defcribed 
as being fomewhat fmaller than the common wild 
goofe. The head grey; the neck adorned with 
a red ring; the breafl, wings, and neck, grey; and 
the feet red. Ray feems to queflion the reality of 
this account. 
E R M 
ERICA. An appellation given by fome na- 
turalifls to the common herring, the chalcis of 
Ariflotle. 
ERINACEUS. See Hedge-hog. 
ERINOPTERUS. See Privet-Fly. 
ERMINE; the Muflela Erminea of Linnaeus, 
This animal, which is alfo called the Stoat, fo 
greatly refembles the weafel in it's fize and confor- 
mation, that many naturalifls, and Linnfeus among 
their number, have given but one defcription of 
both. 
The Ermine, however, differs from the weafel 
in being nine inches long; whereas the latter fei- 
dom exceeds fix. The tail of the float, vs'hich is 
always tipped with black, is iorfger in proportion 
than the body, and better covered with hair; and 
the edges of the ears, and extremities of the toes, 
are of a yellowifh white hue. But though the co- 
lours of the Ermine and the weafel are nearly alike, 
(being a lightifh brown in ftunmer and white in 
winter in the more northern parts of Europe) even 
then the weafel m.ay be cafily diflinguifhed from 
the Ermine by the tip of the tail, which in the lat- 
ter is always black. 
The fur of the Enriine is well known to be one 
of the moft valuable kinds hitherto difcovered; 
but it is only in winter that it poiTtiTes it's proper 
colour and confidence. During the fummer feafon^ 
the Ermine, as before obferved, is brown. And, in- 
deed, this change of colour in the hair of qua- 
drupeds in fome micafure prevails in all : the horfe, 
the cov/, and the goat, evidently vary their hues 
in the beginning of fummer, the old hair then 
falling off, and fliorter llipplying it's place, but 
generally of a darker and more glofTy hue. 
What in this our temperate climate obtains in a 
fmall degree, prevails in a much greater in thofe 
regions v/here the winters are long and very fevere, 
and the fummers fliort, and yet intenfely hot. 
During thefe lad feafons, the animal divefls itfelf 
of it's v/arm coat of fur, which v/ould prove very 
inconvenient, and continues for two or three 
months in a flate fomewhat refembling that of the 
ordinary quadrupeds of milder climates. At the 
approacli of winter, however, with the increafe of 
the cold, the coat of hair feems to thicken in pro- 
portion : from being coarfe and fhort, it lengtliens 
and grows finer; while multitudes of fmall hairs 
fpringing up between the longer ones, thicken the 
fur to an extraordinary degree, and communicate to 
it all that warmth and foftnefs which is peculiar to 
hyperborean animals. 
To prefent our readers with a philofophical ac- 
count of the caufes of this remarkable warmth in 
the furs of northern quadrupeds, would perhaps be 
attended with fome degree of difEculty. It may 
indeed be faid, that nature thus fits them for the 
climate; and, like an indulgent mother, when flie 
expofes them to the rigours of an intemperate win- 
ter, fupplies them with coverings proper for with- 
flanding them. But though this itiay be true, it 
docs not amount to a phyfical demonflration : how- 
ever, it is obfervable with refpedl to quadrupeds, as 
well as the human fpecies itfelf, that a thin meagre 
diet has a tendency to produce long hair; and that 
children who have been fparingly fed, as well as 
famifhed dogs and horfes, are generally more hairy 
than others whofe aliment has been dealt out to 
them more plentifully. This may perhaps be af- 
figned as one cogent reafon why animals inhabit- 
ing the northern climates are, during the brumal 
feafons, more hairy than thofe of milder ones; for 
