26 LIST OF IISH. 



** Anal distinct; nictitant membrane distinct ; hinder gill-slit over 

 the pectorals ; second dorsal opposite the anal; dorsal unarmed. 



7 . Squalini. — Teeth compressed, triangular, acute; spiracles none, or 

 small. — Sphyrna. — Squalus. — Thalassorhinus. — Scoliodon. — 

 Galeocertlo. — Physodon. — Loxodon.— Galeus. 



8. Triaenodontiui. — Teeth acute, denticulated <>n each side; spiracles 

 small. — Triakis. — Leptocharias. — Triaenodon. 



it. Mustelini. — Teeth small, blunt ; spiracles large. — Mustelus. 



10. Cestracionini. — Anal distinct ; nictitant membrane none; spi- 

 racles large; gill-slits small; hinder over the pectorals ; dorsals 

 armed with spines. — Cestracion. 



11. Scyllini. — Anal distinct; nictitant membrane none; spiracles 

 large; dorsals both nearly over the centrals ; teeth small, acute, 

 denticulated. — Stegistoma. — U<rlismostoma. — Grassorhinus. — 

 Heniiscyllium. — Orectolobus. — Pristidurus. — Scyllium. — ? Rhi- 

 naodon. 



Dr. S. Miillerand Henle (Mag. Nat. Hist. ii. 1838) published an 

 outline of their system. He divides the sharks into five divisions, 

 thus : — 



Division I. Scyllia, containing 1. Scyllium. — 2. Pristiurus. — 



3. Chiloscyllium. — 4. Hemiscyllium. — 5. Crossorhiuus. — 6. Gin- 

 glymostoma. — 7. Stegostoma. 



II. subdivided thus: a. with membrana nictitans. a. without 

 spiracles, a. teeth flat, sharp-edged, serrated, or smooth. 1. Carcha- 

 rias. — 2. Scoliodon. — 3. Zygssna. b. teeth pointed with a lateral 

 denticle-like tooth of Scyllium. I. Triamodon. — 2. Leptocharis. 

 B. icith spiracles, a. teeth flat, part serrated, or not serrated. 1. 

 Galeocertlo. — 2. Loxodon. — 3. Galeus. b. teeth pointed, as in 

 Scyllium. 1. Triakis. e. teeth pavement-like. 1. Mustelus. — 2. 

 No nictitating membrane (Lamnoidea). 1. Lamna. — 2. Oxyrhina. 

 — 3. Carcharodon. — 4. Selache. — 5. Rineodon. b. Trichoghis. — 

 c. Alopecias. — d. Cestracion. 



III. Notidanus, Cuvier. 1. Hexanchus. — 2. Heptanchus. 



IV. a. Acanthorinus. 1. Acanthias. — 2. Spinax. — 3. Centrina. 

 — 4. Centrophorus. b. Scymnus. 1. Scymnus. — 2. Laemargus. — 

 3. Echiuorrhinus. 



V. Squatina. 



