The “Greenland Shark” is an inhabitant of the Arctic regions, but rarely straying to the latitudes of great Britain; it grows to a length of about 15 feet, and, although it never or but rarely attacks man, is one of the greatest enemies of the whale, which is often found with large pieces bitten out of the tail by this Shark. Its voracity is so great that, according to Scoresby, it is absolutely fearless of the presence of man whilst engaged in feeding on the carcass of a whale, so that it can be pierced through with a spear or knife without being driven away. It is stated to be viviparous, and to produce about four young at a birth. [Illustration: Fig. 124.--Læmargus borealis, Greenland Shark.] ECHINORHINUS.--Two very small dorsal fins, without spine, the first opposite to the ventrals. Skin with scattered large round tubercles. Nostrils midway between the mouth and the end of the snout. Teeth equal in both jaws, very oblique, the point being turned outwards; several strong denticulations on each side of the principal point. Spiracles small. The “Spinous Shark” is readily recognised by the short bulky form of its body, short tail, and large spinous tubercles. It is evidently a ground-shark, which probably lives at some depth and but accidentally comes to the surface. More frequently met with in the Mediterranean, it has been found several times on the south coast of England, and near the Cape of Good Hope. _Euprotomicrus_ and _Isistius_ are two other genera of this family; they are pelagic and but little known. NINTH FAMILY--RHINIDÆ. _No anal fin; two dorsal fins. Spiracles present. Pectoral fins large, with the basal portion prolonged forwards, but not grown to the head._ RHINA.--Head and body depressed, flat; mouth anterior. Gill-openings rather wide, lateral, partly covered by the base of the pectoral. Spiracles wide, behind the eyes. Teeth conical, pointed, distant. Dorsal fins on the tail. The “Angel-fish,” or “Monk-fish” (_Rh. squatina_), approaches the Rays as regards general form and habits. Within the temperate and tropical zones it is almost cosmopolitan, being well known on the coasts of Europe, eastern North America, California, Japan, South Australia, etc.; it does not seem to exceed a length of five feet; it is viviparous, producing about twenty young at a birth. Extinct forms, closely allied to the “Angel-fish,” are found in the Oolite, and have been described as _Thaumas_. The carboniferous genus, _Orthacanthus_, may have been allied to this family, but it was armed with a spine immediately behind the head. TENTH FAMILY--PRISTIOPHORIDÆ. _The rostral cartilage is produced, into an exceedingly long, flat lamina, armed along each edge with a series of teeth_ (saw).