PROF, AG ASSIZE 



Here it is older, [Plate II, fig. B.] It is what 

 we call pupa, but it is only an older caterpillar and 

 not yet fully grown. These are simply stages 

 in one and the same animal ; and we have been 

 misled by ideas which we had formed from what 

 the ancients called metamorphosis; we have 

 been allowed to let ourselves think that they were 

 one class of beings transforming themselves into 

 other beings ; but they are not. They are all one 

 thing in different stages. 



As is the caterpillar, so- is the pupa ; and so is 

 the perfect animal, the butterfly. The animal re- 

 mains in the first condition for a certain time, and 

 changes his condition and remains in the second 

 condition a certain time, and finally arrives at its 

 last transformation. And before it can undergo 

 guch changes, is had to be formed. And in the 

 changes which the substance of the egg itself un- 

 dergoes, it is the substance of the egg which gives 

 rise to such a priaaative form, and then undergoes 

 metamorphosis. 



[PLATE VII EGGS OF 



longitudinal line marked beneath, [Fig; C.J 

 here, [Fig. D] we have, after certain transforma- 

 tions, an animal with its blood vessels, growing 

 towards the perfeet form. And in this way we 

 have tbe various transformations or metamor- 

 phoses take place. 



In other animals the metamorphoses are gradu- 

 al. We see, for ins-tance, the tadpole, from the 

 singular form first seen [Plate III. fig. A} passing 

 gradually into the form of a frog. But every 

 metamorphosis takes place gradually, not seem- 

 ingly from one animal to another, but by changes 

 of the same animal to others and other forms. 



[PLATE III FROGS 1 



This is the egg ot a musquito, [Plate VII, fig. A ] 

 And there is the external mass [Fig. B,] making 

 its appearance. After some changes, it becomes 

 divided externally, and when the little worm which 

 is within the egg escapes, it is in the form of a 

 larva. It then undergoes transformations by which 

 it finally assumes its perfect form. 



[PLATE VIII EGGS OF RABBIT?.! 



A transformation takes place in all animals. 

 This [Plate VIII, fig. A,] represents the egg of a 

 rabbit. It undergoes similar changes to those in 

 the fish. It gives rise to the prominent mass as 

 seen here, [Fig. B.] This spreads, and there i8 a 



Now, it will be the knowledge of this metamor- 

 phosis of animals which I intend to make the 

 foundation of a natural system of Zoology. And 

 how that is to be done, I will explain by an exam- 

 ple, and refer to the class of reptiles ; as I find it is 



