70 COMPARATIVE ANATOMY CHAP. 



Sub-Order 1. Siphonanthe. 



The heteromorpliic persons bud on a variously formed stem, which may be com- 

 pared with the gastric peduncle of a Medusa. 



Family 1. Calyconecta. Without pneumatophore and feeler (taster) ; with one 

 or more swimming bells at the upper end of the stem. The remaining hetero- 

 morpliic persons arranged in groups (cormidia), which can detach themselves 

 from the stem as Eudoxicc and ETSCCCK, Praya (Fig. 85, p. Ill), Dipliyes, 

 Abyla, Hippopodius. 



Family 2. Physonecta. With pneumatophores, without aurophore, with several 

 swimming bells, and with feelers. Apolcmia, Agnlma, Anthcmodcs, Hali- 

 stcmuia, Physopliora, Forskalia. 



Family 3. Auronecta. With one large pueumatophore, under which stands a 

 circle of swimming bells, and in the dorsal middle line of the latter a large 

 medusoid air bell (aurophore), which secretes gas, and may be considered as a 

 modified swimming bell. Stem shortened and thickened. Without feeler (?). 

 Stephalia (Fig. 84, p. 110), Auralia, Ehodalia. 



Family 4. Cystonecta. With large pneumatophore, without aurophore. 

 Swimming bells and covering pieces wanting. PJiyzophysa, Physalia. Stem 

 under the pneumatophore very much shortened, and flattened into a disc. 



Sub-Order II. Disconanthe. 



The heteromorpliic individuals bud from the under side of a disc, which contains 

 a many-chambered pneumatophore, and may be compared with a Medusa umbrella. 

 The margin of the disc carries a ring of numerous tentacles. In the middle of the 

 subunibrella stands th central gastric peduncle as chief siphon. 



Family 5. Disconecta. Discalia, Porpita, Porpalw. (Fig. 87, p. 114), Velella. 



Sub-Class II. Scyphozoa. 



Prototype : The Kcyphapolyp or the Scyphula. In the Scyphozoa we find an 

 ectodermal oesophagus. Gastral or niesenterial filaments are present in all cases on 

 the septa or gastric ridges. The sexual products arise out of the endoderm. The 

 sexes are generally found in separate individuals. 



Order 1. Anthozoa (Corals). 



Attached individuals or colonies. The body remains essentially on the same 

 grade as the Scyphula. The ectodermal oesophagus sinks in the form of a tube into 

 the spacious gastric cavity, and round it the latter is divided by septa into a variable 

 number of separate pouches. The free internal edges of these septa run through 

 the gastric cavity to the aboral end of the body. 



A. Octocorallia. 



Sub-Order 1. Alcyonaria. Generally with 8 septa and 8 pinnate tentacles. Polyp 

 colonies of very various shapes. Skeletal forms very varied. Ah-i/im /"//<, 

 Pennatula, Kopliobclemnon (Fig. 63), Gorgonia, Isis, Tubipon'. 



B. Tetracorallia. 



Sub-Order 2. Rugosa. Number of septa great, a multiple of 4. With calcareous 

 skeleton. Fossil Paleozoic forms. 



