SQUALL 151 



Extinct genera are Orodus Ag., Campodus de Kon., Sphenacanthus Ag. , 

 Carboniferous Limestone ; Hybodus Ag., Trias to Cretaceous ; Palaeo- 

 spinax Eg., Lias ; Acrodus Ag., Trias to Cretaceous, etc. 



Fam. 4. Scylliidae. Dog-fishes ; asterospondylous, dorsal fins 

 without spine ; first dorsal above or behind the pelvic ; an anal fin ; no 

 membrana nictitans ; spiracle distinct ; mouth inferior ; teeth small ; 

 nostrils near the mouth, sometimes confiuent with it, sometimes with cirri. 

 Scyllium Cuv. (Scylliorhinus Blainv.), upper edge of caudal fin smooth ; 

 Sc. canicula Cuv., small-spotted dog, single nasal flap, pelvic fins separated ; 

 eggs laid in April, hatched in December ; Sc. catidus Cuv., large-spotted 

 dog, nurse hound, nasal flap divided, pelvic fins almost conjoined ; Pris- 

 tiurus Bon., snout much produced, small flat spines along upper edge of 

 caudal fin, P. melanostoinus Bon. ; Ginglymostoma ^i. and H., large sharks 

 of the warm seas, nostrils confluent with mouth ; Stegostoma M. and H., 

 tiger-shark to 15 feet, India ; Parascyllium Gill, Tasmania, 2^ feet ; 

 ChiloscylUum M. and H., nasal and buccal cavities confluent, Indian and 

 Australian, 2\ feet ; Ctossorhinus M. and H., Australia and Japan to 10 

 feet, mouth nearly anterior, nasal and buccal cavities confluent. 

 Extinct genera : Palaeoscyllium Wagn., Upper Jm-assic ; Mesiteia 

 Ivramb., Cretaceous. 



Fam. 5. Carchariidae. Asterospondylous ; first dorsal opposite space 

 between pectoral and pelvic, without spine ; an anal ; with nictitat- 

 ing membrane ; mouth crescentic, inferior ; spiracles present or absent. 

 Carcharias M. and H. (sub-genera, Scoliodon M. and H., Physodon M. and 

 H., Aprionodon Gill, Hypoprion M. and H., Prionodon M. and H.) com- 

 prises the true sharks ; no spiracle ; teeth with a single cusp, snout pro- 

 duced, pit at root of tail ; temperate and tropical ; C. glaucus Cuv., 

 blue-shark, 25 ft. ; C. gangeticus of the Ganges and inland lakes of the Fiji 

 Islands, and C. nicaraguensis G. and B. , Lake Nicaragua, only fresh- 

 water sharks known, 7 ft. ; Hemigaleus Bleek, East-Ind. Archipelago ; Loxo- 

 don M. and H., Ind. Ocean ; Galeocerdo M. and H., arctic, temp, 

 and trop. seas ; Thalassoi-hinus M. and H., Med. and Atl. ; Galeus 

 Cuv., small spiracle, teeth with single cusp, snout elongated, no pit at 

 root of tail, temp, and trop., viviparous ; G. canis Rond., tope, 

 whithound, penny dog, miller's dog, 7 ft. ; Zygaena Cuv. {Sphyrna 

 Raf.), temp, and trop., no spiracles, hammer-headed sharks, eyes at 

 extremity of head lobes ; Z. malleus Shaw, hammer-shaped head, vivi- 

 parous, balance fish ; Triaenodon M. and H., no spiracles. Red Sea, 

 Ind. Ocean ; Leptocarcharias Smith, no spiracles, S. Africa ; Triads 

 M. and H., Ind. and Pac. Oceans ; Mustelus Cuv., viviparous, teeth flat 

 and paved, temp, and trop. seas, spiracles small, no pit at root of tail, 

 bottom-flsh ; M. laevis Risso, embryo attached to uterus by placenta ; 

 M. vulgaris M. and H., no placenta, 6 ft., smooth hovuid, skate-toothed 

 dog. Scylliogaleus Blgr., Natal. 



Fam. 6. Lamnidae. Mackerel sharks. Large sharks with large 

 teeth ; first dorsal opposite space between pectoral and pelvic, without 

 spine ; asterospond ylous ; an anal fin ; no nictitating membrane ; mouth 

 crescentric, inferior ; spiracles absent or minute, varying even in the same 

 species ; pelagic, attain large size. Lamna Cuvier, Porbeagles, teeth 

 lanceolate, large, with smooth edges, keel at side of tail, temperate and 

 tropical seas ; L. cornubica Gmelin, Porbeagle (porpoise and beagle) or 

 Beai-unaris shark, viviparous, 10 ft. ; Carcharodon M. and H., C. rondeletii 

 M. and H., great blue-shark, man-eater, spiracle minute or absent, Med. to 



