nsFUSOBIA. 



61 



horny 'carapace,' wdthin which the animal can re- 

 treat when alarmed ; and, in some cases, additional 

 protection would seem to be afforded by a valve 

 placed obliquely across the upper end of this 

 sheath (^fig, 14, a). In Lagotia (b) the rotatory 

 organ terminates in a pair of mde ciliated lobes 

 which are seldom seen at rest during: the life of 

 the animal. In Ophrydhnriy the most anomalous. 



Fig. 14. 



Marine Infusoria : — o, Vaginicola valvata, showing animal 

 extended and valve (^) raised ; a', the same, showing animal 

 contracted within its sheath and valve (<^') shut down ; — b, 

 Lagotia viiidis, showing rotatory organ | ; b', young animal of 

 preceding, 



perhaps, of all the true Infusoria, the several 

 animalcules, though sometimes foimd detached, 

 are more frequently embedded in the interior of a 

 greenish gelatinous substance, which sometimes 

 occurs in masses of such extent as to have been 



