60 THOUGHTS ON ANIMALCULES. 



(that is, of a crystalline appearance). The sheath is iso- 

 lated, granular, and of an elongated conical form, and is 

 composed either of lenticular, hexagonal, or pentagonal 

 bodies, produced by a viscid exudation from the base 

 of the animal, that hardens in the water. The en- 

 velope of the body is at first transparent, the granular 

 coat being of subsequent formation. If the newly- 

 hatched young are put into water, and a drop of a 

 solution of carmine or indigo be added from time to 

 time, the case will be party-coloured ; for zones of red 

 or blue globules will be formed, alternating with 

 white ; as in pi. v, fig. 5. A very young example is 

 seen, fig. 3, with but one ring of corpuscles, which is 

 coloured by the carmine: in figs. 2, 4, the same in- 

 dividual is represented when of more advanced age, 

 and the sheath consists of several zones of corpuscles. 



The young has two eyes, which disappear in the 

 adult. 



Near the neck there are two respiratory tubes, (pi. v, 

 fig. 5, a a), which are very prominent in the young 

 state. 



The MELICERTA, like the Limnias, is an exceedingly 

 susceptible animal, concealing itself within its case upon 

 the slightest agitation of the water. It is a beautiful 

 object when its rotatory organ is fully spread out, and 

 the cilia in rapid motion. 



