THE COASTS OF SICILY. 47 



bodies in the lower plants, which M. Thuret has 

 made known to us, and which for some hours present 

 the characters of animality. 



It is not possible, however, long to remain in doubt, 

 for the embryo unfolds itself, becomes elongated, and 

 throws out at its anterior part a minute smooth 

 tubercle, bearing on its surface and on each side of 

 it a round eye-point. From this moment its nature 

 is definitely fixed. The observer cannot yet, it is 

 true, recognise the class, family and genus to which 

 the nascent being which he is observing belongs; 

 but he may boldly affirm that when it has reached 

 its perfect state, this being will be an articulate 

 animal, for it already possesses all the fundamental 

 characters of this great sub-division. Its body is 

 composed of two symmetrical lateral halves, its dorsal 

 and ventral surfaces may be clearly distinguished, its 

 digestive canal stretches from the front to the pos- 

 terior part of its body. Everything still seems to be 

 homogeneous in this microscopical embryo ; we dis- 

 cover no muscle, and yet it contracts in every direc- 

 tion, rolls itself into a ball, or flattens itself into a 

 disc, and in these extreme movements it exhibits 

 temporarily those forms which deceived the skilful 

 Swedish naturalist. 



At this epoch it is still impossible to recognise a 

 priori if the embryo will become an Annelid, or if, 

 stopping at the last series of the sub-division, it may 

 belong to the groups of smooth worms, as, for instance, 

 to the Nemertes. Our uncertainty is here of short du- 

 ration, for rings appear upon the body and are rapidly 

 multiplied, being always formed successively from 



