The DERE GRY oo ENS EC DS: 
#04 
A particular treatife on the Frog and its young, exhibiting its bifory, and com- 
paring it with infects. 
Tas. XLVI: 
A Comparifon of the metamorphofis, and, 
if I may be allowed the expreffion, a 
- tranfcretion of the parts, happening in young 
Frogs, with that obferved in the Nymphs of 
infects. 
As, in the preceding fheets, I have occa- 
fionally, though flightly, touched on the like- 
nefs of the change of limbs in the larger or 
fanguiferous animals, to that which infects un- 
dergo; I fhall here delineate and explain this 
fubje&t more at large, in order to make the 
knowledge of it diftinc: and clear. For this 
purpofe *, ; 
Tab. XLVI. N°. 1. exhibits the Frog’s real 
egg, or the Worm of the young Frog, enclofed 
in its firft coat. It reprefents a fmall @ black 
globule, furrounded 44 by another globe, con- 
fitting of a clear, clammy, and glutinous mat- 
ter. This matter is the real food of the Worm 
of the Frog, which now lies within, covered 
as yet with its proper integuments: therefore 
the Frog’s Vermicle or Worm may be confi- 
dered as the yolk, and the food the white of 
this ege. 
N°. ir. I lightly exprefs the invefting coat 
or integument before mentioned. It is here 
caft offc, and rolled back d@to the hinder part of 
the Frog. It likewife appears, in this figure, 
how much the furrounding aliment is now 
dilated, eee. Hence the young Frog is cir- 
cumftanced exactly in the fame manner as all 
Worms and Caterpillars of each of the four 
orders are, when they have caft their firft coat, 
or their ege-fhell; in which I call them Ovi- 
form-Nymph-Animals, or Oviform-Nymph- 
Vermicles, as may be feen particularly in the 
fourth order, where the egg is confidered. 
N°, 111. It is delineated to the life how the 
young Frog, called a Tadpole by authors, 
{wims in the middle of its food, and alfo in 
what manner that food appears in the water 
like a difperfed cloud, fff. The Vermicle or 
Worm itfelf is here delineated much larger 
than it was, when it firft began to fwim into 
its food, immediately after quitting its fhell, or 
firlt membranaceous integument. Therefore 
one may now very diftin€ly fee its head, breaft, 
and body. But becaufe the perfon, who I fhall 
defire to diftinguifh thefe parts, ought to have 
a thorough knowledge of them, thofe who 
inveftigate nature but fuperficially, look into 
that globe only for the young Frog’s head, 
though it really comprelrends the whole body; 
as the incomparable Harvey has before juft ob- 
ferved. At the extremity of this young Frog’s 
body is feen a long continued tail, Tab. XLVI.. 
N®. 11. 4, by the help of which it fwims; 
* There is {carce any animal which has the principle of life fo ftrong as the F Tog. 
‘guts are taken out. An Eel is celebrated for this ftrength of life; but the F 
bious; for it will live for a length of time equally well on land without wat 
been tied down under water many days, and received no hurt, nor fuffered any feeming inconvenience. 
4 
fince the Frog is, whilft it wears that form, 4 
real footlefs Worm, and, in this refpect, re- 
fembles the feetlefs or apode Vermicles or 
Worms of the firft mode in our third order. 
Here it muft be well obferved; that the 
young Frogs never confume their food entirely; 
which, for that reafon, is diluted by the im- 
bibed fluid, and gradually attenuated ; fo that; 
at laft, it refembles a little cloud floating in the 
water. Indeed, that gluy cloud is infenfibly di- 
lated to fuch a degree, that it feemsdefigned for 
the young Frog as a place to reft in, when it thall 
think proper: for which reafon it is likewife 
obferved, that, when tired with {wimming, it 
quickly penetrates into this cloud, and there 
remains without motion. 
And here I fhall beg leave to obferve fur- 
ther, that as the infects which are found in 
cheefe, putrified fleth, and many fruits, and in 
tubercles, lie furrounded with their nourith- 
ment; fo, in like manner, the young Frog 
{wallows its food, at this time, through its 
mouth, as they do. -There is however this 
difference, that the young Frog is nourifhed 
while it yet lies in the integument or-coat of its 
eggs; and this I could never obferve with re- 
{pect to any other infects. ‘The infects, in ge- 
neral, lie in the coats of their eggs, in the fame 
manner as Butterflies do in their Caterpillars, 
and only increafe in ftrength. Therefore, I do 
not doubt but the young Frog is provided with 
umbilical veffels, of which matter I thall after- 
wards treat in its place. 
N°. rv. I reprefent how the hinder legs 72 
are obferved to increafe in the Tadpole, or 
young Frog; that is, whilft they infenfibly 
{pring out of the body, as the cups of flowers 
from out of their footftalks, or as the cafes 
wherein the wings of infects are at firft repo= 
fited: fo that the young Frog is, in this re- 
{pe&, very like thofe little creatures defcribed 
under the fecond order; though it again differs 
from them, in that it is produced from the 
egg in form of a footlefs Worm. 
I likewife obferve, that about this time the 
young Frog’s fore legs are infenfibly increafed 
and augmented, under the fkin, in fuch man- 
ner as I have before explained, in regard to the 
Worms and Caterpillars of the third order. 
For this reafon one may likewife plainly dif 
tinguifh, with the naked eye, the rudiments 
of the legs, if the fkin be then opened in that 
part. And this is likewife the cafe in all the 
Worms and Caterpillars juft mentioned, as I 
have occafionally exhibited in the former 
tables. 
Tab. XLVI. N°. v. I here reprefent, to the 
life, how all the limbs of the young F rog have 
It will continue moving many hours after the 
rog exceeds it greatly. No creature is fo truly amphi- 
er, and abfolutely immerged in water. A Frog has 
at 
