72 Introduction to Animal Morphology. 



moniliform pulsating vesicle. 14. Stentoridce funnel-shaped, 

 naked (Stentor), or surrounded by a gelatinous capsule, \vith 

 a spiral peristome of long cilia, mouth and anus close in the 

 same groove ; nucleus moniliform ; front of the body two- 

 valved (Freia) or ribbon-like, spirally inrolled (Chaetospira). 



Sub-order 4. Hypotricha only ciliated on one (the 

 under) side ; including four families. 15. Oxytrichidae pos- 

 sessing bristles (Oxytricha, Fig. 8, A), hooks (Kerona), or styles 

 (Urostyla), or both hooks and styles (Stylonychia), by help of 

 which they can walk ; shell-less, or with verv thin test and 

 marginal cilia ; one form (Kerona polyporum) is parasitic in 

 Hydra. 16. Kuplotidce with a distinct test, hooks and 

 styles, ex. Kuplotes. 17. Dystrrkhu with a tail-like foot, 

 and a membranous carapace of two separate (Iduna), or united 

 valves (Hysteria), or with no carapace (Huxleya). 18. Aspi- 

 discidae shield-shaped, with a test; cilia reaching to the 

 anten : pharynx nt obvious; locomotory process as in 



Euplotidcu, but with no fine eilia. 



CHAPTER XI. 



SUB-KINGDOM II. POLYSTOMATA (IIil.\ 



AQUATIC animals, made up of differentiated plastides, 

 bounding a central cavity, thus forming Gastrulae. 

 The cavity communicates with the external water by 

 many pores or interstices between the cells of the wall, 

 as well as by one or more terminal mouths or oscula 

 formed by absorption at one point in the Avail of the 

 polyplast (Placckcl , or by imagination (in Sycon 

 ciliatum, Metschnikof\ Sexual reproduction often 

 occurs, but there are no highly specialized tissues. 



There is one class included : 



CLASS i. PORIFERA (Grant) Sponges, whose 

 characters are those of the sub-kingdom. 



