524 



C(ELHELMINTHES. 



CHILOSTOMATA the cystids can be closed by an operculum : Gemmel- 

 laria* Cellularia* Bugula* Flustra* (fig. 295), Esehara* The 

 CYCLOSTOMATA have tubular cysthls without an operculum. Crisia* 



• ft) m 



Fig. 396,— American gymnolseinatous Polyzoa. 

 Verrill.) A^ Tubuiipora fldbe/lxris, young 

 chelata ; D, Genielhi, ■ - ■ ■ ^ ^. 

 fera ; G, Forella Icei 



(After Busk, Hincks, Xorman, and 

 B, Flimtrella hispida : C. Eucraiea 

 a loricnid ; E, Kinetoskias .'■■mitti; F, Menibranipora spini- 

 ; H, Lepralia aniericana : J, Cribillina punctnrata. 



Tubuiipora,'' llornera^ In tlie CTENOSTOMATA the cystid is more cal- 

 careous and tlie opening is closed by a, folded membrane. Alcyonidium^* 

 Vesicularia^ Valkeria.^ PalwliceUa'^ (fresh-water). 



Order II. Phylactolaemata (Lophopoda). 

 Tentacles borne on a horseshoe-shaped lophophore extending on either 



Fig. 397.— Small folony of Lophopns crystallinus {after Kraepelin), "with young and 

 old, some extended, others more or less retracted, o, statoblasts. 



side of the mouth, the tentacles on its margins. All ai'e fresh-water 

 species. I*ectu/.attlia,* LnpJiopus (fig. 227), PJumateUa:^ 



