620 



COMPENDIUM OF GENERIC DISTINCTIONS. 



Si'/uis. As Mii.irs. —Teeth mi palate. Cornea of eye divided 

 transversely. Head flattened between eyes. Nostrils in short 

 tube. Surinam. 



Family. CYPRINIDiE. — Body with rounded scales. One 

 rayed dorsal. Mouth small and toothless. Inferior pharyngeal 

 bones with large teeth. Branchiostegals three. 



Genus, (vi'kims. — Head naked. Branchiostegals flat and 

 broad. Anal fin short. Fresh waters. 



Genus. I'lM'i. — Dorsal and anal fins short. Rarbules very 

 small. Scales small. Ponds and rivers. 



Genus. Ami amis. — No barbules. Body deep and compressed. 

 Base of anal long. Lakes and rivers. 



Genus, Leuciscus. — Dorsal and anal short. Barbules none. 

 Fresh w aters. 



Family. SILVRTDM.— Body naked or shielded. In most the 

 first ray of dorsal and pectoral a spine with moveable joint. 



Genus. Silurus. — Body naked. Teeth very numerous. Dor- 

 sal small, single near head. Anal long. Barbules four to six, 

 some very long. Seas and rivers. 



Order. PLECTOGNATHI.— Upper jaw-bones immoveably 

 joined to sides of interniaxillaries. Body tVith shield's or spines 

 and scales. 



Family. SCLERODERMI. — Snout conical or pyramidal. 

 Mouth tootled, in front of snout. Body with hard scales or 

 cuirassed. 



Grmif. ( Istk lciok. — Teeth ten to twelve in each jaw. Body 

 tri- or quadrangular, cuirassed, with holes for tail, fins, and 

 mouth. Tropical seas. 



Genus. Balistes. — Body compressed. Eight teeth in each 

 jaw. First dorsal formed of one or several spines. Second dorsal 

 near tail, soft. Tropical seas. 



Genus. Oriosoma. — Anal spines wanting. Scales none. 

 B0113 protuberances on body. Atlantic. 



Family. GYMN0D0NTES.— Jaws projecting from mouth, cov- 

 ered with solid tooth-ivory. 



'Villi's. DlODON. — Jaws not divided. Warm seas. 



Genus. TiiioixiN. — Upper jaw divided. Warm seas. 



Genus. Tkthoiion. — Both jaws divided. Warm seas. 



Genus. OrthraGORISCOS. — Body very short, deep, and com- 

 pressed. Jaws not divided. Dorsal and anals connected with 

 tail-tin. Many seas. 



Order. LOPHOBRANCH I ATA. — Gills composed of small 

 round tufts, the operculum very large and the aperture very 

 small. Body covered with bony rings. 



Family. PEGASID.E.— Breast very wide; pectorals long, with 

 nine or ten spiny rays. Mouth below snout (like that of the 

 sturgeon i. Breast-ring very broad, with two spines. Tail-tin 

 with ten strong raj's. 



Genus. Pegasus, — As family. Warm seas. 



Family. SYNGNATHIDiE.— Body long. No first dorsal or 

 ventral. Anal very small or wanting. Males with egg-pouch. 

 Gill-aperture small and circular. 



Genu*. Hippocampus. — Tail prehensile at tip, without tin. 

 Hind part of head elevated. Most seas. 



Genus. StnGN'ATHUS. — Snout long, cylindrical, without spines, 

 Body seven-sided. Most seas. 



Order. GANOLEPIDOTI. — Body covered with strong, bony, 

 enamelled scales. 



Genus. LefidoSTECS. — Jaws long and narrow. Scales in ob- 

 lique rows, tending backward. Dorsal small and near tail. 

 Vertebrae extending to upper lobe of tail. North America. 



Order. CYCLOSTOMI.— Body cylindrical. Branchiae with 

 six or seven spiracles on each side. 



Family. PETR0MYZ0NID.E;.— Lip circular or horseshoe, shape. 

 Two dorsals. 



Genus. Lampktka (including Petromyzon). — Mouth circular, 

 with hard tooth-like processes. Branchial apertures seven. No 

 pectorals or ventrals. Seas and rivers. 



Genus. IIkotkia. — Skin of throat dilated into pouch. Rivers, 

 Australia. 



Genu*. Ammociktks. — Lip of horseshoe shape. Mouth not 

 toothed. Rivers. 



Genus. Myxine. — Dorsal very long and broad, running round 

 tail. Lip surrounded with barbules. Mouth with a single hook- 

 like tooth, tongue with two rows of teeth on each side. Bran- 

 chial apertures two. Many seas. 



Order. LEPTOCA R Dl I .—Pulsating vessel instead of heart; 

 blood pale. Dorsal cord instead of vertebras. 



Genus. Amphioxds. — Body sharp at both ends. Dorsal run- 

 ning round body. Mouth below, a mere longitudinal slit. Many 



DIVISION. IN VE11TEBR AT A 



Animals without vertebra', true heart, or brain. 



CL A .SS.-MOLLTJSK8. 



Invertebrate animals loith soft bodies, enclosed in muscular skin — Mostly with an univalve, or bivalve shell. 



Genus. Argonauta. — As family. Warm seas. 



Sub-dans. CEPHALOPODA —Two sides symmetrical. Jaws 

 powerful anil vertical. Eves large, on sides of head; cephalic 

 ganglion i.e. the knot of nervous matter which takes the place 

 of the brain 1 protected by cartilage. Arms set round head. 



Order. DIBRANCHIATA.— Eyes sessile and prominent; jaws 

 homy; anus with suckers. Two gills. Ink-gland present. 



S OCTOPODA. -Anns eight; eyes fixed. 



Family. ARGONAUTTD.ffi.— Dorsal arms of female webbed at 

 tips, and secreting a delicate shell. Mantle rupported in front 

 l v a single ridge on the funnel. 



Family, OCTOPODIDJE— Arms not webbed, united at base 

 by mantle. Two short styles in mantle instead of shell. 



'oiois. CtRRHOTEUTHIS. — Two fins on body. Arms united 

 nearly to tip; suckers in single row. Northern seas. 



Section. DECAPODA. — Arms ten. Tentacles two. 

 Suckers on footstalks. Shell loose in mantle. 



Family. TEUTHIDS). — Body long; fins short and broad. 



Shell horny. 



