THE COASTS OF SICILY. 59 



We see, therefore, how much we have advanced 

 since the period when Reaumur called the Medusae 

 masses of living jelly, and when Cuvier believed with 

 other naturalists in the existence of Parenchyma- 

 tous Worms. In proportion as zoologists have more 

 thoroughly investigated the mysteries of the inferior 

 world, organisation seems to have grown more com- 

 plicated, and to have assumed the most unexpected 

 forms. Let us beware, however, of falling into an 

 opposite extreme. After having admitted without 

 sufficient proof; and by a sort of a priori reasoning, 

 the organic simplicity of the lower animals, we must 

 not conclude from a few already known facts, that 

 they all present an equal degree of complication. At 

 the lowest point of the zoological scale, there exist 

 beings in which all the vital acts are accomplished, 

 simultaneously and in the same manner, over all por- 

 tions of the body, and whose organs appear to be 

 fused together into one homogeneous structure. I 

 will here give a few examples by way of illustration. 



In the living sponge, a sort of semi-fluid varnish 

 covers with a thin stratum that horny and more or 

 less solid skeleton, which is so familiar to all of us. 

 This varnish is the actual animal, the structure which 

 we commonly term sponge, being, in fact, its skeleton. 

 The Amoeba, which is still more simple, appears to 

 be nothing more than a drop of this living varnish 

 endowed with locomotion, but not having even a 

 determinate form. The eye when aided by the micro- 

 scope may see these animals flow together into a 

 mass, as drops of oil would flow over the slide, while 

 they present the most diversified and irregular forms. 



