shark \shark\ shaumrk, n. of uncertain origin; perhaps
   through of. fr. carcharus a kind of dogfish, gr. karchari`as,
   so called from its sharp teeth, fr. ka`rcharos having sharp
   or jagged teeth; or perhaps named from its rapacity cf.
   shark, v. t.  i.; cf. corn. scarceas.
   1. zool. any one of numerous species of elasmobranch fishes
      of the order plagiostomi, found in all seas.
      1913 webster

   note: some sharks, as the basking shark and the whale shark,
         grow to an enormous size, the former becoming forty
         feet or more, and the latter sixty feet or more, in
         length. most of them are harmless to man, but some are
         exceedingly voracious. the man-eating sharks mostly
         belong to the genera carcharhinus, carcharodon, and
         related genera. they have several rows of large sharp
         teeth with serrated edges, as the great white shark
         carcharodon carcharias or carcharodon rondeleti
         of tropical seas, and the great blue shark
         carcharhinus glaucus syn. prionace glauca of all
         tropical and temperate seas. the former sometimes
         becomes thirty-six feet long, and is the most voracious
         and dangerous species known. the rare man-eating shark
         of the united states coast carcharodon atwoodi is
         thought by some to be a variety, or the young, of
         carcharodon carcharias. the dusky shark
         carcharhinus obscurus is a common species on the
         coast of the united states of moderate size and not
         dangerous. it feeds on shellfish and bottom fishes.
         1913 webster

   note: the original 1913 webster also mentioned a "smaller
         blue shark c. caudatus", but this species could not
         be found mentioned on the web august 2002. the
         following is a list of atlantic ocean sharks:
                        
         common and scientific names of atlantic sharks
                        
         from "our living oceans 1995" published by the
         national printing office:
         nmfs. 1999. our living oceans. report on the status of
         u.s. living marine resources, 1999. u.s. dep. commer.,
         noaa tech. memo. nmfs-f/spo-41, on-line version,
         http://spo.nwr.noaa.gov/olo99.htm.
         the following list is found at at
         http://spo.nwr.noaa.gov/app5.pdf
         1 pelagic sharks
         thresher shark alopias vulpinus
         bigeye thresher alopias superciliosus
         oceanic whitetip shark carcharhinus longimanus
         sevengill shark heptrachias perlo
         sixgill shark hexanchus griseus
         bigeye sixgill shark hexanchus vitulus
         shortfin mako isurus oxyrinchus
         longfin mako isurus paucus
         porbeagle lamna nasus
         blue shark prionace glauca
         2large coastal sharks
         sandbar shark carcharhinus plumbeus
         reef shark carcharhinus perezi
         blacktip shark carcharhinus limbatus
         dusky shark carcharhinus obscurus
         spinner shark carcharhinus brevipinna
         silky shark carcharhinus falciformis
         bull shark carcharhinus leucas
         bignose shark carcharhinus altimus
         galapagos shark carcharhinus galapagensis
         night shark carcharhinus signatus
         white shark carcharodon carcharias
         basking shark cetorhinus maximus
         tiger shark galeocerdo cuvier
         nurse shark ginglymostoma cirratum
         lemon shark negaprion brevirostris
         ragged-tooth shark odontaspis ferox
         whale shark rhincodon typus
         scalloped hammerhead sphyrna lewini
         great hammerhead sphyrna mokarran
         smooth hammerhead sphyrna zygaena
         3 small coastal sharks
         finetooth shark carcharhinus isodon
         blacknose shark carcharhinus acronotus
         atlantic sharpnose shark rhizoprionodon erraenovae
         caribbean sharpnose shark rhizoprionodon porosus
         bonnethead sphyrna tiburo
         atlantic angel shark squatina dumeril
         pjc

   2. a rapacious, artful person; a sharper. colloq.
      1913 webster

   3. trickery; fraud; petty rapine; as, to live upon the shark.
      obs. --south.
      1913 webster

   basking shark, liver shark, nurse shark, oil shark,
   sand shark, tiger shark, etc. see under basking,
      liver, etc. see also dogfish, houndfish,
      notidanian, and tope.

   gray shark, the sand shark.

   hammer-headed shark. see hammerhead.

   port jackson shark. see cestraciont.

   shark barrow, the eggcase of a shark; a sea purse.

   shark ray. same as angel fish
      a, under angel.

   thrasher shark or thresher shark, a large, voracious
      shark. see thrasher.

   whale shark, a huge harmless shark rhinodon typicus of
      the indian ocean. it becomes sixty feet or more in length,
      but has very small teeth.
      1913 webster
see also:
shark plagiostomi carcharhinus carcharodon carcharodon carcharias carcharodon rondeleti 
carcharhinus glaucus prionace glauca carcharodon atwoodi carcharhinus obscurus c. caudatus 
alopias vulpinus alopias superciliosus carcharhinus longimanus heptrachias perlo hexanchus griseus 
hexanchus vitulus isurus oxyrinchus isurus paucus lamna nasus carcharhinus plumbeus 
carcharhinus perezi carcharhinus limbatus carcharhinus brevipinna carcharhinus falciformis carcharhinus leucas 
carcharhinus altimus carcharhinus galapagensis carcharhinus signatus cetorhinus maximus galeocerdo cuvier 
ginglymostoma cirratum negaprion brevirostris odontaspis ferox rhincodon typus sphyrna lewini 
sphyrna mokarran sphyrna zygaena carcharhinus isodon carcharhinus acronotus rhizoprionodon erraenovae 
rhizoprionodon porosus sphyrna tiburo squatina dumeril basking shark liver shark 
nurse shark oil shark sand shark tiger shark basking 
liver dogfish houndfish notidanian tope 
gray shark hammer-headed shark hammerhead port jackson shark cestraciont 
shark barrow shark ray angel fish angel thrasher shark 
thresher shark thrasher whale shark rhinodon typicus