.1 REVIKW OF Tin-: ASIMAL CROVI'S Il'J 



FF, Body cyliiidrioiil, without hypostoino, with stomodeum and 

 mesenteries subdividing the Ra-strovascuhir cavity; scsflilc 



without stalk; single or colonial Class Anlhozoa 



EE. Body jelly-like in consistency, with eight n)W8 of ciliated 

 swimming plates, tentacles present or absent but without 



nemaU)cysts Phylum Ctcn^iphora 



UD. Symmetry bilateral, body depressed ..Phylum I'latyhiiminihcs 

 E. Moutli and digestive system present. 



F. Without sucking di.scs about moutli or upon other i)arts of 



the body Class TurbcUaria 



FF. Sucking discs present Class Trematoda 



EE. Mouth and digestive system absent, body elongate and 

 divisioned into flat units (Roman girdle-like), one end of 

 body undivisioncd, narrow with terminal enlargement 



liearing hooks or adhesive cups or both Class Cistoda 



CC. Anus presejit, mouth provided with accessory parts such as lobes; 

 palps; hooks, special areas or crowns of cilia; chitinous, calcareous, 

 or bony jaws; teeth, etc. 

 D. Skeleton absent or external in location. 



E. Sj'mmetry radial. Radii usually five or multiple thereof. 

 Surface of body with hard plates and spines or leathery with 



small calcareous plates Phylum Echinodirmata 



EE. Symmetry bilateral, sometimes curved or arrangdd in a spiral. 

 F. True metamerism lacking or if the body appears metamcric 

 (annulated) it will bear cilia upon the anterior end. 

 G. Calcareous or horny sliolls ab.sent, or if present they arc 

 tubular or of two valves placed dorsally and ventrally, 

 the ventral valve curved dorsally at narrow end. 

 H. Body wormlike without crown of tentacles on anterior 

 end. 

 I. With eversil)le proboscis which when not everted 

 rests in a sheath above alimentary canal. Proboscis 

 with one or more stylets at end but without hooks 



Pliylum Nemrrlinea 

 IF. Without evcrsible proboscis. When such a structure 

 is present it is permanently extended and its surface 

 is beset with hooks. Body slender and covered with 

 glistening cuticle. Expanded lips with teeth some- 

 times present Phylum N emathelminthes 



HII. Body usually not wormlike but if so the anterior end 

 will l)car tentacles. 

 I. With one or more crowns or girdles of cilia borne 

 upon the discoidal or lobed anterior end. Micro- 

 .scopic in size, not colonial . .Phylum Trochrhninthta 

 II. With an oval or horseshoe-shaped lophoi)hore, bear- 

 ing tentacles. Calcareous or horny shells may be 

 pre.sent as tubular ca.ses or as valves dorsal and 

 ventral in position. Those without shells are 

 colonial, the individuals resting in cases, tubes, or 



