ICHTHYOLOGY. 



323 



English Channel, or both sides of the Atlantic, in the Medi- 

 terranean, Bay of Bengal, Indian Archipelago, and seas of 

 Australia, China, and Japan. We have transferred the 

 family o^ Zi/genid<E^ from its place after the Carcharidm in 

 Miiller and Henle's Plagiostornen^ to the neig^hbourhood of 

 the SquatinidcBj where it stands in Owen*s table. 



Order XL— PLAGTOSTOMI. 



Endo-skeleton cartilaginous or partially ossified; exo-skeleton 

 placoid. Gills with five or more apertures. No swim-bladder. 

 Scapular arch detached from the head. Ventrals abdominal; in- 

 testine with spiral valve. Copula gaudent. 



Sub-Order I.— SQUALL 



Plagiostomi, with lateral gill-openings. Free supplementary 

 eyelids; incomplete scapular arch ; and no naso-pectoral cartilage. 



ANALYTICAL TABLE OF THE SQUALl (Dura.) 

 Pectorals not notched. 



Head short, obtuse ; teeth tricuspid; gi^l-^^P^'i" 1 Opvtttttm 



ings over pectorals J 



Spout-holes none. 



Forehead abnormal, wide, eyes laterally stilted.... Zyq^iax. 

 Forehead of the usual squaloid form. 



Gill-openings before the pectorals Lamna. 



Gill-openings over the pectorals Carcharias. 



Spout-holes present. 



Teeth serrated, denticulated. 



Dorsals two Gale us. 



Dorsal solitary NOTIDANUS. 



Teeth not denticulated^ 

 Teeth fiat. 

 Anal distinct. 



Dorsal pointed Mustelus. 



Dorsal rounded Cestracion. 



Aiial wanting ; dorsals with spines Spinax. 



Teeth not flat. 

 Teeth trenchant. 



Dorsals with spines Centrina. 



Dorsals without spines Scymnus. 



Teeth conical, pointed, very numerous Selache. 



Pectorah notched in front, affording space for the gill- 1 qqtt . mT« . 

 openings,., J 



(A.) Sharks, with an anal fin, and the dorsals far hack; the 

 first being behind the ventrals. 



Family L— SCYLLIID^. 



ScyUia^ Miill. and Henle. Spout-holes. No nictitating mem- 

 brane. Five gill-openings, the last one over the base of the pec- 

 toral fin. A furrow at the corner of the mouth ; an upper and 

 under labial cartilage. Teeth with a pointed medial cusp, and 

 four or five radical toothlets on either side. Caudal longitudinally 

 extended, truncated or rounded at the end, with or without a trace 

 of an under lobe, but having a notch on the under side near the 

 end; no caudal pit; oviparous. Eggs resembling those of a Skate; 

 intestinal valve spiral. 



Genus L Scyllium, Miill. and Henle. First dorsal between 

 the ventrals and anal ; the second between the anal and caudal. 

 Spout-holes close behind the eyes. Gill-openings equidistant, the 

 last pair over the pectoral. Snout short, blunt; nostril near the 

 mouth, connected with it by a furrow, and having a valve. Der- 

 mal ossicles or scales tricuspid. Eleven species. 



Genus II. Pristiurus, Bonap. Scyllia, but with an elongated 

 snout. Upper edge of the caudal serrated by a row of flat spine- 

 lets; a trace of an under caudal lobe; second dorsal over the end 

 of the anal. Eggs smooth as in ScyHium. One species. 



Genus IIL Hemiscvllium, Miill. and Henle. Nostrils reach- 

 ing to within the mouth ; nasal flaps distinct, outer one large, 

 inner one with a barbel. Spout-holes large, longitudinal under the 

 hinder half of the eyes. Gill-openings as in Scyllium. Both dorsals 

 behind the ventrals and before the anal, which latter is close to the 

 caudal ; caudal notched, without an under lobe. Two species, vide 

 fig. U. 



Genus IV. Chiloscyllium, Miill. and Henle. A broad cuta- 

 neous under lip, with a transverse furrow behind it; the elongated 

 under fold at the corner of the mouth attached in the middle. Teeth 

 pointed, with one or two radical toothlets on each side. Spout- 

 holes longitudinal, close behind the eyes. Fourth and fifth gill- 

 openings close together. Dorsals placed as in Hemiscy Ilium. Six 

 species. 



Genus V. Crossorhinus, Miill and Henle. Mouth large, Classifica- 

 nearer the end of the snout than in most Sharks. Head broad and tion — 

 flat ; many cutaneous tags about the nasal flaps and. sides of the Sharks. 

 head. Teeth trilobate. Spout-holes unusually long, beneath and ^^.^^^^^ 

 somewhat behind the eyes. Gill-openings equidistant, decreasing 

 in size from first to the last, which is over the pectoral. Dorsals 

 between t!ie ventrals and anal, the latter close to the caudal. One 

 species. 



Genus VI. Cinglymostoma, Miill. and Ilenle. (iVt;6Wws, RUpp.) 

 Snout blunt; a Icng barbel from the inner side of the nostrils; 

 corner fold of the mouth divided by a deep transverse furrow, the 

 under portion subdivided by a longitudinal furrow. Teeth very 

 numerous, in ten successive rows, each having a simple rhomboidal 

 base, a conical mesial point, and from two to four toothlets on each 

 side. Fifth gill-opening almost concealed within the fourth. Spout- 

 holes very small, directly behind the eyes. First dorsal over the ven- 

 trals ; caudal very long, having a rudimentary under lobe ; pectorals 

 long. Two species. 



Genus VII. Stegostoma, Miill. and Henle. Mouth small, 

 quiie transverse. Teeth small, tripartite. The skin between the nasal 

 flaps wider than the flaps, and forming an outer upper lip. A stout 

 barbel, formed by a prolongation of each nasal flap. Corner folds 

 of the mouth short, with deep pits. Head depressed and rounded. 

 Spout-holes perpendicular slits behind the eyes. Fifth gill-open- 

 ing concealed within the fourth ; the last three over the pectoral; 

 caudal very long, almost of even height throughout, and notched 

 as usual towards the end. One species. 



(B.) Sharks, ivith two dorsals and an anal ; the first dorsal 

 over the space hetiveen the p>ectorals and ventrals. 

 nictitating membrane. No spout- holes ; the last two 

 gill-openings over the pectoral. 



Family II.— CARCHARIDiE. 



CarcharicB, MijU. and Henle. Nostrils generally small, with a 



three-sided flap on their upper border. Pupil perpendicularly 

 oval. Mouth boldly convex, with a small corner fold. Teeth com- 

 pressed, triangular, with an entire or serrated cutting edge. Cau- 

 dal always with a short under lobe, and a notch below near the end 

 of the upper lobe. A pit above and below at the base of the tail. 

 Intestinal valve rolled longitudinally, not spirally. Scales small. 

 Skin smoothish. 



Genus I. Carcharias, Miill. and Henle. Nostrils midway be- 

 tween the mouth and end of the depressed snout. Labial carti- 

 lages small or wanting. Yelk-bag connected with a kind of uterine 

 placenta; oviduct smooth or villous. 



Sub-Gemts I. Scoliodon. A mesial tooth in the upper jaw, none 

 in the lower one ; cutting edges of the teeth entire, not serrated. 

 Second dorsal over the anal or its hinder end. Tail-pits distinct. 

 Upper and lower caudal lobes equal. Scales small, three-keeled. 

 Oviduct villous. Three species. 



Sub-Genus II. Physodon. Teeth like those of Scoliodon, but 

 thicker and larger, and there are two small teeth on the mandible, 

 opposed to the single mesial upper tooth. First back fin close be- 

 fore the ventrals, the second over the anal. One species. 



Sub-Genus III. Aprion. Teeth not serrated ; upper teeth straight 

 or slightly inclined outwards ; under ones straight, with a small 

 point on a broader base. Three species. 



Sub-Genus IV, Ilypoprion. Base of the upper teeth strongly ser- 

 rated or jagged on one or both sides ; their cusps smooth ; no ser- 

 ratures on the bases or points of the lower teeth. Two species. 



Sub-Genus V. Prionodon. Teeth in one or both jaws finely ser- 

 rated, oblique or straight, three-sided, or with a small cusp on a 

 broad base; generally a solitary mesial under tooth. Oviduct 

 smooth. Twenty species. 



Genus II. Prionodon, Miill. and Henle, (Leptocarias, Smith.) 

 Nasal flap broad or prolonged into a barbel. Orbits longitudinal. 

 Corner folds of the mouth very small. Teeth of Scyllia, small and 

 numerous, alike in both jaws. Second dorsal and anal opposite, or 

 nearly so. Caudal as in Carcharias, or as in those ScylUidcc, in which 

 the under lobe is scarcely perceptible. Scales from three to seven 

 keeled. Two species. 



(C.) Sharks, with two dorsals and an anal; first dorsal 

 between the pectorals and ventrals. A nictitating nie'in- 

 brane. Spout-holes. The last tivo gill-openings over 

 the pectoral. 



Family HI.— GALEIDiE. 



Galei, Mull, and Henle. Nostrils, orbits, mouth, and its corner 

 folds as in the CarcharidcB, but with small labial cartilages. Spout- 



