ACINETAKIA. 51 



Scypliidia Lachmann, ectopar. ; Gerda Clap, and L., f.w. ; Astylozoon Engelmann, 

 f.w. ; Vorticella L., with long contractile fibre for attachment, f.w. and m. ; 

 Carchesium Ehrb., colonial, f.w.; Zoothamnium Ehrb., colonial, f.w. and m. ; 

 Glossatella Blitschli, attached, but without stalk; Epistylis Ehrb., colonial, 

 and Ehabdostyla Kent, solitary, stalk without contractile fibre ; OpcrJularia 

 Goldf. ; Ophrydium Bory ; Cothurnia Ehrb. ; Vaginicola Lam. ; Lagenophrys 

 Stein, with lorica. 



Forms of uncertain position : 



Multicilia Cienk., covered by long flagella-like cilia, m. and f.w.; Grassia 

 Fisch, covered with long cilia, parasitic in stomach of frog and in blood of 

 Hyla viridis ; Magosphczra Haeckel, free-swimming ciliated forms occurring 

 in spherical colonies. 



SUB-CLASS III. ACINETARIA. 



Infusoria with knobbed tentacle-like processes which serve as sucking 

 tubes. Ciliated in the young state. 



These animals are always sedentary in habit, and either free or 

 attached; when the latter they may be sessile or stalked. They 

 prey upon the living tissues of other organisms by means of 

 their tentacles. The latter 

 are processes of the cor- 

 tical protoplasm, and are 

 of two main kinds, con- 

 necting which there are 

 intermediate forms : (1) the 

 so-called prehensile tenta- 

 cles which taper distally, 

 although they do not end 

 in a sharp point, and (2) 

 the suctorial, which are 

 cylindrical in shape and 



rounded at the end, which FlG - ^--^cineta femuaMquinum Ehrb., sucking the 

 . body of a small infusorian (Enchelys), after Lachmann. 



may even be swollen into T suctorialtentacle ; V vacuole ; N nucleus. 



a distinct knob. 



The tentacles of both kinds appear to contain a canal which opens 

 distally to the exterior, and leads at the other end into the central 

 protoplasm of the body. The fluid or semi-fluid contents of their 

 prey pass down these canals in a current, the cause of which is not 

 quite understood. Maupas has suggested that the transparent ecto- 

 plasm of the Acinetan first passes in an invisible current by the 

 tentacle into the body of the prey, there absorbs the protoplasm, and 

 then returns with its burden to its own body in a current which can 

 be traced by the granule contents of the protoplasm. All tentacles 



