802 



COMPENDIUM OF GENERIC DISTINCTIONS. 



Family. RHIZOSTOMADiB. No central orifice to 

 stomach. Food received through ends of branching canals. 



Genus. RHIZOSTOMA. Ovaries four. Footstalk with four 

 or eight semilunar apertures. 



CLASS. ZOOPHYTA. 



Radiate, gelatinous, or fleshy, with tentacles round 

 mouth Stinging weapons. 



Order. ACTINOIDA. Internal cavity enclosing stomach, 

 and divided into compartments by radiated walls. Germs 

 thrown out of cavity at sea. 



Sub-order. ACTIN ARIA. Tentacles twelve or more. 

 Seldom tubercled ; radiating partitions often depositing solid 

 chalky plates. 



Family. ANTHEAD^E. Base adherent at pleasure. 

 Column smooth, not pierced ; edge simple. 



Genus. ANTHEA. Base slightly adherent, broader than 

 column. Summit of column expanding. Tentacles numerous, 

 in several rows, very long, hardly retractile. 



Family. ILYANTHID^E. Base not adherent, lower ex- 

 tremity rounded and simple. 



Genus. ILVANTHUS. Tentacles of one kind, on edge. 

 Column thick and pear-shaped. Mouth simple. 



Genus. EDWARDSIA. Column slender, with epidermis. 



Family. SAGARTIAD^. Base adherent. Column 

 pierced. 



Genus. ACTINOLOB^B. Tentacles moderate. Disc retract- 

 ile. Column with suckers. 



Genus. SAGARTIA. Column with suckers. 

 Family. BUNODIDvE. Column warty. Base adherent. 

 Genus. BUNODES. Warts bold, arranged in vertical lines. 

 Family. ACTINIADjE. Edge headed. 



Genus. ACTINIA. Acontia wanting. Base much wider 

 than column. Tentacles wholly retractile. - 



Family. LUCERNARIAD^E. No cord. Tentacles in 

 remote groups. (N. B. Mr. Gosse, in his " British Sea-Ane- 

 mones and Corals," excludes this family, believing it to be 

 properly placed with the Medusae.) 



Genus. LUCERNARIA Body bell-shaped, adherent or free 

 at will. Tentacles knobbed, in groups or angles of disc. 



Family. FUNGIBLE. Polypary free, rounded, or oval ; 

 convex above, concave below. Plates radiating from centre to 

 circumference. 



Genus. FUNGIA. Round, the plates with very fine teeth. 

 Hot seas. 



Family. CARYOPHYLLEAD^E. Tentacles crowded ; 

 mouth capable of protrusion. 



Genus. CARYOPHYLLEA. Corallum simple, or fixed by 

 adhesion. Plates converging in three series; sponge-like mass 

 of twisted plates at bottom of cup. Animal with mouth 

 ribbed ; tips of tentacles knobbed. 



Genus. LOPHOPHELIA. Corallum branched ; stem long, 

 solid, and smooth. 



Family. GYROSA. Cells united into waving furrows. 

 Plates on both sides. 



Genus. MEANDRINA. Polypary stony and hemispherical. 

 On convex side stars winding and lamellated. Hot seas. 



Genus. EUPHYLL^EA. Polypary leaf-like ; stars on both 

 side. Hot seas. 



Family. MADREPORID^E. Tentacles twelve, short ; 

 polypary stony. 



Genus. MADREPORA. Cells lamellated, isolated; inter- 

 stices prominent. Warm seas. 



Family. TUBULIPORID^E. Polypary composed of 

 parallel tubes, fixed by transverse partitions. 



Genus. TUBULIPORA. As Family. Indian seas. 



Family. CORTICATA. Polypary fixed, branching; axis 

 solid and stony. Polypes retractile. 



Genus. CORALLIUM. Shaft uniform, rigid, with five longi- 

 tudinal furrows. Mediterranean. 



Genus. Isis. Jointed ; the junctions horny. Hot seas. 



Sub-order. ALCYONARIA. Tentacles warty or plumed; 

 branchlets perforated. Corallum, when present, mostly chalky, 

 sometimes horny, rarely flinty. 



Family. GORGONIAD^E. Fixed, plant-like, forming 

 secretions from epidermis. 



Genus. GORGONIA. Axis horny; not jointed. Crust soft 

 and fleshy. 



Family. PENNATULAD-fli. Free, and feather-shaped. 



Genus. PENNATULA. Shaft nearly cylindrical. Pinnae 

 two-ranked and spreading, having polypes on upper edges. 



Genus. VIRGULARIA. Polypary long and slender ; polypes 

 on a series of curved projections. 



Family. ALCYON I ID-dE. Polypary attached, fleshy, with 

 numerous chalky spicules ; irregular. 



Genus ALCYONIUM. Polypary lobed ; pores star-shaped, 

 from which the polypes emerge. 



Order. HYDROIDA. Internal cavity simple, increasing 

 by buds from sides. 



Family. TUBULARIADjE. Buds not permanent, near 

 base of tentacles. Animals naked, or in horny tubular envel- 

 ope. 



Genus. TUBULARIA. Inclosed. Not branched. Polypes 

 with two circles of tentacles ; egg-germs on footstalks. 



Family. SERTULARIAD^E. Egg-germs in vesicles. 

 Buds permanent, in horny envelope. Polypes in sessile cells. 



Genus. SERTULARIA. Plant-like ; stem tubular, branched, 

 and jointed. Cells alternate, or in pairs on opposite sides. 



Genus. PLUMULARIA. Simple or branched, feathery ; cells 

 mostly in angle of branches. Egg -vesicles scattered. 



Family. CAMPANULARIAD^. Cells on footstalks, 

 rest as in preceding family. 



Genus. CAMPANULARIA. Creeping or erect ; cells at ends 

 of long-ringed stalks or in whorls ; embryos medusa-shaped. 



CLASS. ROTIFERA. 



Microscopic, contractile, with cilia affront of body ; 

 resembling wheels when in motion Intestines dis- 

 tinct ; apertures two, one at each extremity of body. 



System as yet uncertain. 



CLASS. RHIZOPODA. 



Form mutable, no external organs or cilia Moving 

 by processes protruded or withdrawn at pleasure. 



System as yet uncertain. 



CLASS INFUSORIA. 



Microscopic Form often mutable ; no apparent ves- 

 sels or nerves Mostly with internal cavities. 



System as yet uncertain. 



CLASS. PORIFERA. 



Form various, fixed, composed of horny fibres or flinty 

 or calcareous spiracles. 



System as yet uncertain. 



