144 L e u c k a r t : Bciicht über die Leistungen in der Nafuigeschichte 



4. Paludicellea. Polypide completely retractile ; evagination of 



tentacular sheath imperfect. 



5. Cyclostomata. Polypide completely retractile; evagination 

 perfect; orifice of cell destitute of moveable appendage. 

 (Adde: Position of the orifice of the cell terminal. Cells 

 arise by gemmation one from the other.) 



6. Ctenostomata. Polypide completely retractile ; evagination 

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

 tion and acting as an operculum in the letracted state. 

 (Adde: orifice terminal. Cells arise each separately from 

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

 conimunicates.) 



7. Cheilostomata. Polypide completely retractile ; evagination 

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

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

 by gemmation one from another.) 



(Die Zusätze sind nach den Bemerkungen des Recensenten in 

 dem Journ. micr. Sc. VI. p. 36 hinzugefügt.) 



Die Süsswasserformen vertheilen sich dabei folgendermaassen : 

 L phop e a: 



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. Statoblasts orbicular, with an annulus and marginal 

 spines. 



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



Fam. Plumatellidae. Conoecium rooted. 



Gen. Pectinatella Leidy. Lophophore with two long arnis. 

 Conoecium massive; ectocyst gelatinoid ; statoblast orbicular, with 

 marginal spines. 



Sp. P. magnifica Leidy. 



Gen. Lo phop US Dum. Lophophoie with two long arms. 

 Conoecium sacciform; ectocyst gelatinoid; statoblasts oval, destitute 

 of spines. '»'" .-«ii'»''''' 



Sp. L. crystallinus Pall. 



Gen. Alcyonella Lam. Lophophore with two long arms. 

 Conoecium tubulär, tubes united ; ectocyst pergamentaceous. 



Sp. Ale. fungosa Pall. , Ale. Benedeni Allm. , Ale. flabellum 

 van Ben. 



Gen. Plumatella Lam. Lophophore with two long arms. 

 Conoecium tubulär, tubes distinct; ectocyst pergamentaceous. 



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

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



