PLANARIA PANNICDLATA. 41 



nevertheless pinnate interanea are percep- 

 tible by the microscope, which renders it 

 probable that a nutritious substance is 

 there received. The colour daily alters, 

 and in the lapse of three weeks from their 

 origin, some whose progressive increment 

 had been studied, were changed to brown. 

 About twenty marginal specks were visible 

 in the earliest stage. 



The planaria panniculata is rather more 

 inactive than the rest. Penetrating the 

 folds and recesses of decaying vegetables, 

 it lurks entire days in absolute immobility. 

 In common with its kind, it is liable to the 

 attack of a, disease which always proves fa- 

 tal, and extirpates numbers, almost before 

 the observer becomes aware of its ravages. 

 A swelling commences at the posterior ex- 

 tremity, which rapidly ascends to the head, 

 destroying the texture of every part in its 

 advances; and the whole animal is sudden- 

 ly resolved into a kind of whitish floccu- 

 lent matter. 



