Chap. IX.] 



XlPHACANTHA. 



277 



113) thus formed may be variously ornamented; the 

 stalk, well known in Vorticella, is not contractile in 

 Epistylis and others, The lorica may be produced 



Fig. 112, -XivhacantJia murrayana. (After Wyville Thomson.) 



into tooth-like or tail-like processes ; a shield-shaped 

 test, or a bivalved carapace may be developed, or the 

 body may become surrounded by a gelatinous capsule. 

 Karely, as in the Dictyocyrtidse, the investing test 

 becomes impregnated with siliceous bodies. 



