CXXXVl INTRODUCTION. 



filaments in the position of oral tentacles ; mouth and 

 anus approximate ; foot rudimentary or aborted ; mantle- 

 skirt absent ; inclosed in a chitinous or calcareous or 

 gelatinous cell (=mantle shell) ; usually forming colo- 

 nies by continuous gemmation, rarely single. 



Subclass HOLOBHANCHIA, E. Ray Lankester. 



Lophophore either circular or horseshoe-shaped^ bearin 

 an unbroken series of tentacles. 



Group a. Ectoprocta, Nitsche. 

 Anal orifice without the lophophore. 



Order GYMNOL^MATA, Allman. 



Infundibulata, Gervais. 

 Stblmatopoda, Van der Hoeven. 



Polypide destitute of an epistome (foot) ; lophophore 

 circular. 



Suborder I.— CHEILOSTOMATA, Busk. 

 Celleporina, Ehrenberg. 



Orifice of the zocecium closed by a movable opercular 

 valve. Ova usually matured in external marsupia. Ap- 

 pendicular organs (avicularia and vibracula) frequently 

 present. 



Family I. — Aeteidae.* 

 Aetea, Lamouroux. 



* The Aeteidm with the genus Beania ai*e ranked by Carus as a sub- 

 order, tbc Sfolonata, which is thus characterized — "The conical or tubular 

 cells ranged singly on a tubular stolon." But Beania and Adea are not 

 closely related ; the peduncles by which the cells are united in the former 

 are by no means homologous with the creeping stems of the latter, whilst 



