the side of the neck. Labial fold absent or only at angle of lower jaw. Nostrils not connected with mouth (ie. oronasal grooves absent). Teeth dissimilar, in upper jaw one or two pairs of awl-shaped teeth, followed by 6 broader ones with several cusps; lower jaw with 6 large comb-like teeth on either side, posterior teeth smaller. Sx or seven wide gill-slits.

This family is widely distributed in the warmer seas, but contains only a few species, some of which are of large size. Viviparous.

Key to South African genera.

1. Seven gill-slits

2. Six gill-slits

Heptranchias.
Hexanchus.

Gen. HEPTRANCHIAS Raf.

1810. Rafinesque, Caratt. Nuovi Gen., p. 14.

Gill-slits 7. Mouth wide, with labial fold from angle on lower jaw, and a deep groove behind angle. Head broad, depressed; snout broad.

Heptranchias pectorosus (Garman.

Seven-gilled Shark.

1868. Macdonald and Barron, Proc. Zool. Soc., 1868, p. 371, pl. xxxiii (Heptranchus indicus, non Agassiz).

1884. Garman, Bull. Essex Inst., vol. xvi, p. 56.

1913. Id., Mem. Mus. Comp. Zool., vol. xxxvi, p. 20.

1914. Thompson, Mar. Biol. Rep., vol. ii, p. 134 (Heptranchias indicus, non Agassiz. The references belong to another species).

A median pointed tooth in upper jaw, lower median tooth with lateral cusps but no central cusp, 1st cusp of lower teeth larger than the others. Upper edge of tail with 3-6 series of enlarged oval scales. Pupil subcircular. (Plate I, fig. 1.)

Length.-Up to 8 ft.

Colour.-Grey, usually with darker spots or blotches.

Locality.-Agulhas Bank.

Distribution.-S. America, New Zealand, Australia.

Ogilby (1897, Proc. Linn. Soc., N.S. W., vol. xxii, p. 62) describes a pair of jaws, said to have come from the Cape, under the name Heptranchias haswelli, which Garman considers synonymous with the above species; Ogilby, however, states that there is a central cusp to the lower median tooth, which is not the case in pectorosus.

Gen. HEXANCHUS Raf.

1810. Rafinesque, Caratteri Nuovi Gen., p. 14.

Gill-slits 6. Mouth wide, with labial fold on lower jaw at angle. No median tooth in upper jaw.

Hexanchus griseus (Bonnat.).

Six-gilled Shark.

1788. Bonnaterre, Ichthyol., p. 9.

1870. Günther, Cat. Fish. Brit. Mus., vol. viii, p. 397. 1913. Garman, Mem. Mus. Comp. Zool., vol. xxxvi, p. 16.

1922. Norman, Ann. Mag. Nat. Hist., (9), vol. ix, p. 319.

Median tooth of lower jaw with or without a median cusp, laterals of lower jaw with 7 cusps.

Length.-Up to 26 ft.

Colour.-Grey.

Locality. Agulhas Bank, Natal coast.

Distribution.-Atlantic, Mediterranean, Japan.

Fam. 2. CARCHARINIDAE.

Typical Sharks.

Body elongate. Skull hyostylic. Two dorsal fins, without spines, the 1st between pectoral and ventral. Anal present. Pit at root of caudal present or absent, caudal without lateral keels and with lower lobe well developed or obsolete. Nictitating membrane present. Spiracle minute or absent. Labial folds present. Nostrils not connected with mouth (except in Scylliogaleus). Teeth when fully developed hollow, usually with a single large triangular cusp, usually without basal cusps; or the teeth may be small, numerous, and obtuse, or with very indistinct cusps. Five gill-slits.

A large family distributed all over the world, some species ascending rivers, or even living entirely in fresh water. Often of large size. Viviparous as far as is known.

Key to the South African genera.

I. Head not hammer-shaped.

A. A pit at root of tail.

1. Spiracles none. Teeth with a single cusp, smooth or serrated on both Carcharinus.

sides

well as above

2. Spiracles small. Teeth serrated on both sides. A pit below tail as Galeocerdo.

B. No pit at root of tail. Spiracles present though usually minute.
1. Oronasal grooves absent.

a. Teeth with a single cusp serrated on outer margin only

Galeorhinus.

b. Teeth with central acute cusp and 1-2 small basal cusps

Leptocarcharias.

c. Teeth numerous, pavement-like, obtuse or with very indistinct

The position of the genus Scylliogaleus is dependent on the comparative values which students attach to the presence of a nictitating membrane and oronasal grooves. I follow Bridge (Camb. Nat. Hist., 1904, p. 449) and Sedgwick (Text Book of Zool., 1905) in assigning it to the Carcharinidae, although, perhaps, justice is not done. to the phylogenetic significance of the oronasal grooves. Garman (Mem. Mus. Comp. Zool., vol. xxxvi, 1913) places it in his family Galeorhinidae together with Leptocarcharias, Triakis, Mustelus, etc.

Gen. CARCHARINUS Blnvlle. 1816.

(=CARCHARIAS Cuv.)

1816. Blainville, Journ. Phys., p. 264.

Second dorsal and anal fins very small. No spiracles. A pit at root of caudal, which has well-developed lower lobe. Teeth with a single large cusp, serrated or not.

A genus of numerous species, often of large size, chiefly found in the warmer seas. Some live in fresh water.

Key to the South African species.

I. Teeth not serrated (Scoliodon).

A. Preoral length of snout equal to or less than distance from eye to 1st gill-slit. Labial fold not extending on upper jaw acutus.

B. Preoral length of snout greater than distance between eye and 1st gill-slit. Labial fold extending a short way on upper jaw walbeehmi.

II. Teeth serrated (Prionodon).

A. First dorsal nearer pectoral than ventral.

1. First dorsal immediately behind pectoral.

a. Snout broadly rounded, its preoral length much less than width of mouth

zambesensis.

b. Snout pointed, its preoral length not much less than width of

2. First dorsal conspicuously distant from pectoral. Fins with black

extremities.

B. First dorsal nearer ventrals than pectorals

melanopterus.

glaucus.

*Carcharinus acutus (Rüpp.).

Sharp-nosed Shark.

1838. Rüppell, Neue Wirbelthiere. Fische, p. 65, pl. xviii, fig. 4. 1878. Day, Fishes of India, p. 712, pl. clxxxiv, fig. 3.

1914. Thompson, Mar. Biol. Rep., vol. ii, p. 139.

Snout pointed, its preoral length (i.e. from front margin of mouth) greater than width of mouth and equal to or a little less than distance from eye to 1st gill-slit. A very short labial groove at the angle of the mouth extending only a very short way (in young to in adults) along upper jaw. Teeth about 20 in upper, 18 in lower jaw, oblique, not serrated. Hind margin of pectoral slightly concave, upper angle somewhat pointed, reaching beyond origin of dorsal. Length.-Up to 700-800 mm.

Colour.-Grey, whitish below; margins of fins white, upper margin of caudal black.

Locality.-Cape seas.

Distribution.-Indian Ocean to Japan.

Carcharinus walbeehmi (Blkr.).

Walbeehm's Sharp-nosed Shark.

1856. Bleeker, Nat. Tyds. Ned. Ind., vol. x, p. 353. 1870. Günther, Cat. Fish. Brit. Mus., vol. viii, p. 359. 1878. Day, Fishes of India, p. 712, pl. clxxxv, fig. 2.

Snout pointed, its preoral length greater than width of mouth and greater than distance between eye and 1st gill-slit. A short labial groove on both jaws, extending along upper jaw. Teeth about 20 in both jaws, oblique, not serrated. Hind margin of pectoral slightly concave, upper angle somewhat pointed, extending to beyond origin of dorsal. (Plate I, fig. 2.)

Length.-Up to 900 mm.

Colour.-Grey, nearly uniform, the margins of the fins sometimes pale. Locality.-Natal coast, Delagoa Bay.

Distribution.-Indian seas to Japan.

*Carcharinus melanopterus (Q. and G.).

Black-finned Shark; Black Shark (Natal).

1878. Day, Fishes of India, p. 715, pl. clxxxv, fig. 3.

1914. Thompson, Mar. Biol. Rep., vol. ii, p. 139.

Snout rounded, its preoral length less than width of mouth. A very