CHAPTER XXX.

THE TRUE SHARKS.

Order Notidani.--Family Hexanchidæ.--Family Chlamydoselachidæ.--Order Asterospondyli.--Suborder Cestraciontes.--Family Heterodontidæ.--Edestus and its Allies.--Onchus.--Family Cochliodontidæ.--Suborder Galei.--Family Scyliorhinidæ.--The Lamnoid, or Mackerel-sharks.--Family Mitsukurinidæ, the Goblin-sharks.--Family Alopiidæ, or Thresher-sharks.--Family Pseudotriakidæ.--Family Lamnidæ.--Man-eating Sharks.--Family Cetorhinidæ, or Basking Sharks.--Family Rhineodontidæ.--The Carcharioid Sharks, or Requins.--Family Sphyrnidæ, or Hammer-head Sharks.--The Order of Tectospondyli.--Suborder Cyclospondyli.--Family Squalidæ.--Family Dalatiidæ.--Family Echinorhinidæ.--Suborder Rhinæ.--Family Pristiophoridæ, or Saw-sharks.--Suborder Batoidei, or Rays.--Pristididæ, or Sawfishes.--Rhinobatidæ, or Guitar-fishes.--Rajidæ, or Skates.--Narcobatidæ, or Torpedoes.--Petalodontidæ.--Dasyatidæ, or Sting-rays.--Myliobatidæ.--Family Psammodontidæ.--Family Mobulidæ. 523