2 24 APPENDIX 



PHYLUM III. CCELENTERATA 



Radiate animals with a single but often branched internal cavity and no 

 ccelom. 



SuBPHYLUM I. Cnidaria. Coelenterates provided with nettle cells. 



Class I. Hydrozoa (Hydromedusae). Hydroid polyps and jellyfish, the 

 former without mesenterial ridges and the latter with a velum. 



Order i. Hydrariae. Fresh-water hydroids of simple structure. Ex. Hydra. 



Order 2. Hydrocorallinae. Coral-hke marine hydrozoans. Ex. Millepora. 



Order 3. Tubulariae. Hydroids without hydrotheca; medusae with gon- 

 ads on the manubrium. Ex. Pennaria. 



Order 4. Campanulariae. Hydroids with hydrotheca ; medusae with gon- 

 ads on the subumbrella. Ex. Obelia. 



Order 5. Trachomedusae. Hydroids (when present) minute and of sim- 

 ple structure; medusae usually large with gonads on the subumbrella. 

 Ex. Gonionemus. 



Order 6. Narcomedusae. Hydroids wanting ; medusae with lobed rim. 

 Ex. Cunina. 



Order 7. Siphonophora. Free-swimming colonial hydrozoans. Ex. Phy- 

 saHa. 



Class 2. Scyphozoa (Scyphomedusae). Hydroids and jellyfish, the for- 

 mer with mesenterial ridges and the latter without a velum and often of 

 large size. Ex. Aureha. 



Class 3. Anthozoa. Sea anemones and corals; soHtary or colonial poly- 

 poid cnidarians without medusoid generation. 



Order i. Alcyonaria. Anthozoans with eight mesenterial ridges and eight 

 pinnate tentacles. Ex. Corallium. 



Order 2. Zoantharia. Anthozoans with numerous mesenterial ridges and 

 numerous simple tentacles. Ex. Metridium. 



SuBPHYLUM II. Ctenophora. Coelenterates with eight bands of cihated 

 ridges on outer surface. Ex. Mnemiopsis. 



PHYLUM IV. VERMES 



The lower worms. Animals of primitive structure and without paired 

 locomotory appendages or distinct head. 



SuBPHYLUM I. Platyhelminthes. Flatworms ; no anus present in most 

 forms and body cavity filled with a vesicular connective tissue called 

 parenchyma. 



Class I. Turhellaria, Mostly free-living flatworms with ciliated outer 

 surface. Ex. Planaria. 



Class 2. Trematodes, Flukes. Small parasitic flatworms with mostly 

 a branched digestive tract and an anterior mouth. Ex. Fasciola. 



