COMPENDIUM OF GENERIC DISTINCTIONS. 



641 



Sub-family. Euryalina. — Rays much branched. 



Genus. Astrophyton. — Rays repeatedly two-branched. 



Order. CRINOIDEA. — Digestive canal not symmetrical. 

 Chalky shell formed of many moveable pieces. 



Genus. Cumatula. — Rays five, pinnate. When adult, free; 

 when young, seated on stern. 



Genus. Pentacrinus. — Permanently on long footstalk, which 

 is pentagonal and formed of numerous joints. Filaments placed 

 in whorls on footstalk, which does not alter in diameter. Warm 

 seas. 



CLASS.— ACALEPHA. 



Radiate, gelatinous, free — A digestive cavity ivith ra- 

 diating vessels — Poison-threads — Metamorphosis. 



Order. SIPHONOPHORA —Body irregular. No central di- 

 gestive cavity. With sucking organs. Locomotion by con- 

 tractile cavity or sacs filled with air. 



Family. VELELLADiE. — Animal stretched over gristly plate. 



Genus. Velei.la. — Body flat, oval. Oblique crest above; 

 tubular mouth below, surrounded by short tentacles. 



Family. PHYSAXIADa:.— Animal a large air-filled sac, with 

 many tentacles. 



Genus. Physalia. — Air-sac large, oblong, crest-wrinkled. 

 Tentacles near one end, long, variously-shaped. 



Family. DIPHYIDJE.— Animals bell-shaped, double, fitting 

 into each other. 



Genus. Diphyes. — Animals pyramidal, a few points round 

 aperture. 



Order. CTENOPHORA. — Body symmetrical, not disc-shaped. 

 Large central digestive cavity. Locomotion by parallel rows of 

 cilia. 



Family. CALLIANIRIDiE.— Two long, contractile filaments 

 in chambers, one on each side. 



Genus. Cydippe. — Body globular, no lobes nor tentacles. 



Family. BEROID.33.— No contractile filaments nor chambers. 



Genus. Cestum. — Body very flat, wide, and short, edged 

 with cilia. Hot seas. 



Order. DISCOPHORA — Body disc-shaped, oval, or less con- 

 vex. Large central digestive cavity. Locomotion by expand- 

 ing and contracting disc. 



Tribe. GTMNOPTEALMATA — Eye-specks uncovered or 

 wanting. Circulating vessels running to margin, either simple 

 or branched. 



Family. SARSIADJE. — Vessels simple, four. Ovaries in sub- 

 stance of footstalk. 



Genus. Sarsia. — Hemispherical; four tentacles at edge of 

 vessels. Eye-specks four. Stomach in extensile footstalk. 



Family. WILLSIADJE.— Vessels branched. 



Genus. Willsia. — Globular. Ovaries six. Vessels six. 

 Eye and tentacle opposite each branch. Footstalk short. 



Family. JEQUOREADJE.— Vessels more than eight. Disc 

 flattish. Ovaries in a line along vessels. 



Genus. ^Equorea. — Disc rather convex. Vessels very nu- 

 merous. Footstalk wide, cleft into many broad lobes. Tenta- 

 cles slender. 



Genus. Eudura. — Disc very flat. No tentacles nor footstalk. 

 Hot seas. 



Tribe. STEGAl?0PTHAL3IATA.—Y,ye-svecks covered by 

 flaps. Circulating vessels forming a network. 

 Vol III -81. 



Family. MEDUSAD^.— Stomach with a mouth, through 

 which solid food is taken. 



Genus. Chrysaora. — Disc hemispherical, lobed. Many 

 tentacles on edge. Four very long furbelowed arms, not 

 fringed. 



Genus. Medusa. — Disc hemispherical. Many tentacles on 

 edge. Eyes eight. Ovaries, chambers, and fringed arms four; 

 one opening in centre, four at sides. 



Genus. Cyanea. — Disc flattened, rather scolloped; four 

 fringed arms. Tentacles of edge very numerous, set beneath 

 disc. 



Family. RHIZOSTOMADJE.— No central orifice to stomach. 

 Food received through ends of branching canals. 



Genus. Ruizostoma. — 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. 



Sid>-order. ACTINARIA.— Tentacles twelve or more. Sel- 

 dom tubercled; radiating partitions often depositing solid 

 chalky plates. 



Family. ANTHEADJE.— Base adherent at pleasure. Column 

 smooth, not pierced; edge simple. 



Genus. Antiiea. — Base slightly adherent, broader than 

 column. Summit of column expanding. Tentacles numerous, 

 in several rows, very long, hardly retractile. 



Family. ILYANTHIDiE.— Base not adherent, lower ex- 

 tremity rounded and simple. 



Genus. Ilyanthus. — Tentacles of one kind, on edge. Col- 

 umn thick and pear-shaped. Mouth simple. 



Genus. Edwardsia. — Column slender, with epidermis. 



Family. SAGARTIADJE. — Base adherent. Column pierced. 



Genus. Actinolob.e.— Tentacles moderate. Disc retractile. 

 Column with suckers. 



Genus. Sagartia. — Column with suckers. 



Family. BUN0DID.E.— Column warty. Base adherent. 



Genus. Bunodes. — Warts bold, arranged in vertical lines. 



Family. ACTINIAD.E.— Edge headed. 



Genus. Actinia. — Acontia wanting. Base much wider than 

 column. Tentacles wholly retractile. 



Family. LUCERNARIADJS.— No coral. Tentacles in remote 

 groups. iN.B. — Mr. Gosse, in his "British Sea-Anemones and 

 Corals," excludes this family, believing it to be properly placed 

 with the Medusfe.) 



Genus. Lucernaria. — Body bell-shaped, adherent or free at 

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



Family. FUNGID.E.— Polypary free, rounded, or oval; con- 

 vex above, concave below. Plates radiating from centre to cir- 

 cumference. 



Genus. Fungi A. —Round, the plates with very fine teeth. 

 Hot seas. 



Family. CARYOPHYLLEAD.JE.— Tentacles crowded; mouth 

 capable of protrusion. 



Genus. Caryopbyllea. — Coiallum simple, or fixed by ad- 

 hesion. 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. 



