CXXXV1 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 HOLOBRANCHIA, E. Ray Laukester. 



Lophophore either circular or horseshoe- shaped, bearing 

 an unbroken series of tentacles. 



Group a, ECTOPROCTA, Nitsche. 

 Anal orifice without the lophophore. 



Order GYMNOUEMATA, Allman. 



INFUNDIBULATA, Qervais. 

 STELMATOPODA, Van der Hoeven. 



Polypide destitute of an epistome (foot) ; lophophore 

 circular. 



Suborder I. CHEILOSTOMATA, Busk. 

 CELLEPOUINA, Ehrenberg. 



Orifice of the zooecium 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 Aeteida with the genus Seania are ranked by Carus as a sub- 

 order, the Stolonata, which is thus characterized " The conical or tubular 

 cells ranged singly on a tubular stolon." But Seania and Aetea nro 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 



