from eye to 1st gill-slit. Pelvics much nearer 2nd dorsal than 1st dorsal. (Plate II, fig. 7.)

Length.-Up to 700 mm.

Colour. Slaty grey, with irregularly scattered white spots on back and sides, lighter below.

Locality.-Off Table Bay and Natal coast.

Distribution.-Atlantic coasts of Europe and N. America, Medi

terranean.

Squalus acutipinnis Regan.

The Common Cape Dog-fish.

1908. Regan, Ann. Natal Mus., vol. i, p. 248, pl. xxxvii.

1914. Thompson, Mar. Biol. Rep., vol. ii, p. 152.

Snout bluntly pointed.

not grooved. Pectoral in

Nasal flaps bilobed. Dorsal fin spines when laid back extending well beyond vertical from hind end of base of 1st dorsal, apex acute. Pelvics midway between 1st and 2nd dorsals.

Length.-Up to 800 mm.

Colour.-Uniform greyish; pupil emerald green, iris same colour as

body.

Locality.-Table Bay to Natal, to 100 fathoms.
Distribution.-Mauritius.

It is open to doubt whether acutipinnis is specifically distinct from the European blainvilli (Risso). The pectoral fin is said to be longer and sharper in the former, but it must be noted that in acutipinnis this fin is considerably more acute in the than in the and young. The Australian megalops Macleay is another very closely allied species which may not merit a separate name. The relationships of these forms, and also of fernandinus Molina, should be carefully studied. Gilchrist (1922, Mar. Biol. Surv. Spec. Rep., iii, p. 48) states that the spine of the 2nd dorsal is longer in fernandinus than in acutipinnis, and that the fins are edged with white, and identifies the South African form with fernandinus. Regan, however, places fernandinus among the species which have simple nasal valves, but among the many hundreds of specimens that I have handled I have found none with simple nasal flaps. I consider, therefore, that the name of fernandinus is inapplicable to the South African specimens.

Gen. ETMOPTERUS Raf.

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

Dorsal fins with spines which are doubly grooved laterally, 2nd

larger than 1st, behind pelvics. A long, deep groove on each side of transverse mouth. Teeth of lower jaw very oblique, inner margin forming a cutting edge, upper teeth erect, tricuspid. Spiracle wide, above and behind eye. Nostrils on lateral margin of snout. Gillslits narrow. Dermal denticles placoid, granular, or setiform. The species of this genus possess luminous organs. minute but very numerous and aggregated into lines and patches covering very nearly the entire ventral surface of the body.

Key to the South African species.

I. Dermal denticles close-set, irregularly arranged

II. Dermal denticles arranged in longitudinal series, at least on tail. a. Pelvic fins nearer caudal than pectorals

b. Pelvic fins equidistant from caudal and pectorals .

*Etmopterus spinax (Linn.).

Phosphorescent Dog-fish.

1758. Linné, Syst. Nat., ed. 10, p. 233.

These are

1913. Garman, Mem. Mus. Comp. Zool., vol. xxxvi, p. 223. 1922. Gilchrist, Fish. Mar. Surv. Spec. Rep., iii, p. 49.

spinax.

granulosus.

lucifer.

Dermal denticles setiform, close-set, irregularly arranged. Length of base of 1st dorsal (excluding spine) distance from 2nd. Pelvics much nearer caudal than to pectorals.

Length.-Up to 530 mm.

Colour.-Dark brown or black.

Locality.-Off Cape Point, 417 fathoms.

Distribution. Mediterranean and Atlantic coasts of Europe, to 365 fathoms.

Etmopterus granulosus (Günth.).

1880. Günther, Challenger Rep., vol. i, p. 19, pl. ii, fig. C. 1922. Gilchrist, Fish. Mar. Surv. Spec. Rep., iii, p. 49.

Dermal denticles covering whole body except the median ventral surface of snout, the circumference of the mouth, an area surrounding the base of each dorsal fin, and the rays of the fins including the caudal; the denticles are widely enough spaced to show the smooth skin in between, and on the sides of the tail are arranged in longitudinal rows, more marked in ♂ than 9. Length of base of 1st dorsal (excluding spine) distance from spine of 2nd dorsal. Pelvics nearer caudal than pectoral. Length of head to pectoral nearly twice its greatest width. (Plate II, fig. 8.)

Length.-Up to 450 mm.

VOL. XXI, PART 1.

4

Colour.-Uniform dark brown or black.

Locality.-Off Cape Point, 250-800 fathoms.

Distribution.-Chile to Hawaiian Islands, 222-498 fathoms.

Two young specimens ( and 210 mm.) deserve mention because they resemble very closely the adult of the North Atlantic species spinax. Seeing that they were caught in the same locality as the adults described above, one cannot but presume that they should be considered as the same species.

The proportions of the fins are the same, but the dermal denticles are very much more closely set, with a scarcely perceptible longitudinal arrangement on the tail. They cover the whole body, right up to the margins of the fins, except for a narrow ring around the mouth. But for this smooth ring around the mouth the specimens are in perfect agreement with niger.

*Etmopterus lucifer Jord. and Snyd.

1902. Jordan and Snyder, Proc. U.S. Nat. Mus., vol. xxv, p. 79. 1903. Jordan and Fowler, ibid., vol. xxvi, p. 634, fig. 5. 1913. Garman, Mem. Mus. Comp. Zool., vol. xxxvi, p. 226.

1922. Gilchrist, Fish. Mar. Surv. Spec. Rep., iii, p. 49.

Dermal denticles setiform, regularly arranged in longitudinal rows. Length of base of 1st dorsal distance from 2nd. Pelvics equidistant from caudal and pectorals.

Length.-Up to 380 mm.

Colour.-Brown or black.

Locality.-Natal coast, 113-152 fathoms.

Distribution.-Japan.

Gen. ACANTHIDIUM Lowe.

1839. Lowe, Proc. Zool. Soc. London, p. 91.

Two dorsal fins, with spines which are laterally grooved, 2nd spine much longer than 1st. A long, deep groove on either side of the transverse mouth. Nostrils transverse. Snout produced. Teeth triangular, unicuspid, the cusps erect or oblique. Inner angles of pectoral not produced. Gill-slits narrow. Dermal denticles pedunculate, with 3-4 spines.

All the species of this genus are very closely related, and appear to differ only in slight variations in the positions of the fins and the other proportions.

*Acanthidium natalense Gilch.

Long-snouted Spiny Dog-fish.

1922. Gilchrist, Fish. Mar. Surv. Spec. Rep., iii, p. 49, pl. vii, fig. 2. Inner angle of pectoral (according to figure) quadrate and extending to vertical from origin of 1st dorsal. Eye nearer to pectoral than to end of snout. Teeth not described. (Plate III, fig. 1.)

Length.-?

Colour.

?

Locality.-Natal coast, 160 fathoms.

Type in coll. Govt. Marine Survey.

Gen. CENTROSCYMNUS Boc. and Cap.

1864. Bocage and Capello, Diag. fam. Squal., p. 3.

Two dorsal fins, with laterally grooved spines which are small, with only the points projecting, or quite hidden. Mouth with a deep groove on either side. Nostrils oblique. Snout produced. Teeth unicuspid, dissimilar; those in upper jaw small, narrow, erect; those in lower jaw broad with oblique cusps. Inner angle of pectoral not produced. Dermal denticles pedunculate, with flattened ovoid crown. Pupil circular.

Centroscymnus fuscus Gilch. and von B.

Slender-toothed Spiny Dog-fish.

1924. Gilchrist and von Bonde, Fish. Mar. Surv. Spec. Rep. vii, p. 2.

Preoral distance equal to distance between eye and 1st gill-slit. Second dorsal about equal to 1st, points of spines exposed. Dermal denticles on head with 3-5 keels, those on body with concave crowns. Length.-1100 mm.

Colour.-Uniform brown, pupil emerald green.

Locality.-Off St. Helena Bay (32° S., 16° E.), 280 fathoms.
Type in coll. Govt. Marine Survey.

Gen. ATRACTOPHORUS Gilch.

1922. Gilchrist, Fish. Mar. Surv. Spec. Rep., iii, p. 48.

Two dorsal fins, with spines which are laterally grooved, the 2nd being also barbed; 1st dorsal larger than 2nd but the spines subequal. A long, deep groove on either side of the transverse mouth. Nostrils

transverse. Eye large. Snout short. Teeth unicuspid, cutting edge. horizontal except in the median upper tooth which is erect. Inner angle of pectoral produced. Gill-slits narrow. Dermal denticles acuminate, with converging raised ridges.

This genus is very closely related to Centrophorus, differing only in the barbed 2nd dorsal spine. In fact, there seems little reason for separating this one species into a new genus.

*Atractophorus armatus Gilch.

Barbed Spiny Dog-fish.

1922. Gilchrist, loc. cit., p. 48, pl. vii, fig. 3.

The 2nd dorsal spine barbed. (Plate III, fig. 2.)
Length.-355 mm.

Colour.- ?

Locality.-Natal coast, 160 fathoms.

Type in coll. Govt. Marine Survey.

Fam. 9. PRISTIOPHORIDAE.

Saw-sharks.

Body elongate. Skull hyostylic. Two dorsal fins, without spines, 1st in front of pelvics. Anal absent. Spiracles present. Teeth small, with conical cusp on broad base, arranged in several series. Snout produced into a long flat rostrum armed with teeth along each side; the teeth are fixed to the dermis and not embedded in sockets. Nictitating membrane absent. Nostrils not connected with mouth. A pair of long tentacles on ventral surface of rostrum. Five or six gill-slits, lateral in position, all in front of pectoral, which is normally shaped.

The Saw-sharks are not to be confounded with the true Saw-fishes (Pristidae) which belong to the Hypotremata, with ventral gill-slits. With the exception of one species in Japan, the family is confined to Australasia and South Africa.

As regards the structure of the vertebra of Pliotrema warreni, Ridewood (1921, Ph. Tr. Roy. Soc., B379, vol. ccx, p. 374, fig. 24B) states that there are 8 radiating projections from the central calcified ring. His figure is taken from a vertebra just behind the 1st dorsal fin, though he has apparently examined a complete skeleton. In 2 adult specimens I find that behind the 1st dorsal there are 8 rays, but that anterior to this fin there are 10 rays. In embryos (290 mm.) there is a calcified ring, but no projecting rays.