Chap. 74.] GENEEATION Or EISHES. 463 
to be distinguished by the eyes and tail ; very soon, how- 
ever, the feet are developed, and the tail, l3ecoming bifurcate, 
forms the hind legs. It is a most singular thing, but, after a 
life of six months^ duration, frogs melt away^^ into slime, 
though no one ever sees how it is done ; after which they come 
to life again in the water during the spring, just as they were 
before. This is effected by some occult operation of I^ature, 
and happens regularly every year. 
Mussels, also, and scallops are produced in the sand by the 
spontaneous^^ operations of nature. Those which have a harder 
shell, such as the murex and the purple, are formed from a 
viscous fluid like saliva, just as gnats are produced from liquids 
turned sour,^^ and the fish called the apua,^^* from the foam of 
the sea when warm, after the fall of a shower. 
Those fish, again, which are covered with a stony coat, such 
as the oyster, are produced from mud in a putrid state, or else 
from the foam that has collected around ships which have been 
lying for a long time in the same position, about posts driven 
into the earth, and more especially around logs of wood.^^ It 
has been discovered, of late years, in the oyster-beds,^^ that 
shoot out at the base of the tail, and in the same proportion that they grow, 
the tail decreases, till at last it entirely disappears. 
Frogs, Cuvier says, conceal themselves in mud and slime during the 
winter, but, of course, are not changed into it. 
Quae fuere." Just in the same state, he probably means to say, in 
which they were when they were melted into slime, and not as they were 
when in the tadpole state. 
86 All that is asserted here, Cuvier says, about the spontaneous opera- 
tions of nature is totally false. Everything connected with the eggs and 
the generation of the mussel, the murex, and the scallop is now clearly 
ascertained. 
^'^ " Acescente humore." Hardouin has suggested that the proper 
reading may be " arescente humore" — " from moisture dried up ; " for, he 
remarks, Aristotle, in his Hist. Anim. B. v. c. 18, states, that the 
empides," gnats formed from the ascarides in the slime of wells, are 
more frequently produced in the autumn season. 
s"^* The apuae, or aphyse, Cuvier says, are nothing else but the fry of fish 
of a large kind. 
Cuvier says, that some of the shell-fish deposit their eggs upon stakes 
and piles, which are driven down into the water among sea- weed, and the 
bottoms of old ships : but that many of them perish from the solutions 
formed by those bodies in a state of rottenness, or, at all events, are not 
produced from their decomposition. 
89 " Ostreariis." This was unknown to Aristotle, who, in his work De 
Gener. Anim. B. iii. c. 11, expressly denies that the oyster secretes any 
generative or fecundating liquid. 
