324 



CCELHSLMINTHES. 



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

 laria,* Cellularia* Buyula* Flustra* (fig. 295), Eschara* The 

 YCLOSTOMATA have tubular cystids without an operculum. Crisia* 



-TT 



FIG. 396. American gymnolsematous Polyzoa. (After Busk, Hincks, Norman, and 

 Verrill.) A, Tnbulipora flabellaris, young; B, Flustrella hispida ; C, Eucratea 

 chelata ; D, Gemellaria loricata ; E, Kinetoskias tniitti; F, Membranipora spini- 

 fera ; (?, Porella loevis ; H, Lepralia americana : /, Cribillina puiicturata. 



Ttibulipora,* Hornera* In the CTENOSTOMATA the cystid is more cal- 

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

 Vesicularia, Valkeria.* Paludicella* (fresh- water). 



Order II. Phylactolaemata (Lophopoda). 

 Tentacles borne on , horseshoe-shaped lopliophore extending on either 



Fio. 297. Small colony of Lnphopus crystallfnus (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 are fresh-water 

 species. Pectinatella,* Lopliopus (fig. 227), Plumatella* 



