52 * 



4. Paludicellea. Polypide coinpletely retractile ; evaginatioii of 



tentacular sheath inippifect. 



5. Cycloslomala. Folypide completely retraclile ; evagiiiation 

 perfect; orifice of cell destitute of iiioveable appendage. 

 (Adde: Position of the orifice of Ihe cell terminal, Cells 

 arise by geniniation one fiom the other.) 



6. Clenoslomata. Polypide completely retractile ; evagination 

 perfect; a circle of setae attached to the invertible por- 

 tion and acting as an operculuni in the retracted state. 

 (Adde: orifice terminal. Cells arise each separately from 

 a common tubulär stam, with whose cavity that of the cells 

 communicates.) 



7. Cheilostomala. Polypide completely retractile ; evagination 

 perfect; orifice of the cell with a moveable lip. (Adde: 

 Position of the orifice of the cell sub-teriiiinal. Cells arise 

 by gemmation one froin another.) 



(Die Zusätze sind nach den Bemerkungen des Recensenten in 

 dem Journ. micr. Sc. VI. p. 3G hinzugefügt.) 



Die Süsswasserformen vertheilen sich dabei folgendermaassen : 

 Lophopea: ^ 



Fam. Cristatellidae. Conoecium free, locomotive. 



Gen. Cristatella Cuv. Conoecium sacciform, hyaline, with 

 a common flattened disc adapted for locomotion ; orifices placed on 

 the surface opposide to the disc, and arranged in several concentric 

 marginal series. Slatoblasts orbicular, with an annulus and marginal 

 spines. 



Sp. Cr. niucedo Cuv. (= Cr. mirabilis Dal.) 



Fam. Plumatellidae. Conoecium rooted. 



Gen. Pectinatella Leidy. Lophophore with tvvo long arnis. 

 Conoecium massive; ectocyst gelatinoid ; statoblast orbicular, with 

 marginal spines. 



Sp. P. magnifica Leidy. 



Gen. Lophopus Dum. Lophophore with two long arms. 

 Conoecium sacciform; ectocyst gelatinoid; statoblasts oval, destitute 

 of spines. 



Sp. L. crystallinus Pall. 



Gen. AI c y o n e i 1 a Lam. Lophophore with tvvo long arms. 

 Conoecium tubulär, tiibes united ; ectocyst pergamentaceous. 



Sp. .\lc. fungüsa Pall. , Ale. Benedeni Allm. , Ale. flabellum 

 van Ben. 



Gen. Pluniatella Lam. Lophophore with Iwo long arms. 

 Conoecium tubulär, tubes distinct; ectocyst pergamentaceous. 



Sp. PI. repens Linn. (= PL nitida Leidy ?) PL stricta Allm. 

 (= PL repens van Ben.) , PL punctata Hank. , PL vesicularis Leidy, 



