ON THE OCCURRENCE OF THE CENTRINE SHARK
OFF THE COAST OF CORNWALL.
By Thomas Cornish.
I have recently obtained from a trawler a specimen of the Centrine Shark (Squalis centrina), the first, so far as I can ascertain, taken in English Seas. It was trawled up from a sandy bottom in twenty-six fathom water near the Wolf Lighthouse. It is at all events so rare a fish that I feel justified in giving you some account of it.
The feature which at once distinguishes the fish from all other sharks which I have seen is the presence within the skin and through the centre of the two dorsal fins of a stout spine, the end of which projects beyond the fin. The spine of the first dorsal starts from the base of the horizontal middle of the fin and inclines forward; the spine of the second dorsal starts from about the same relative position and inclines backward; so that each fin is a complete spritsail with the sprit rigged.
The length of my specimen is two feet one inch, over all (Bloch says the fish reaches a length of three or four feet). Its girth immediately before the pectorals, nine inches and four-eighths; girth behind the first dorsal, twelve inches. The head is depressed and broad. The eyes are large and long, with bright green round pupils and no nictitating membrane; over them the orbit is a strong bony ridge, and immediately behind them are blow-holes. Behind them and in front of the pectorals are five very small gill-apertures. The lips are very white and very fleshy and entirely cover the teeth. Bloch apparently described his fish from a specimen dead long enough for the fleshy lips to have dried back.
The mouth is very small. The teeth in the lower jaw are equilateral and in two rows, the outer one consisting of much smaller take than the inner one. The teeth in the upper jaw are numerous and in irregular rows and sharp-pointed, and I think all of them are serrated, but they are all so small that I am not certain about this. The first dorsal stands just over the pectorals, and the second just over the ventrals, and each dorsal has through it the spine I have described, and is free at the rear of the base for about half an inch. The belly is broad and flat; the pectorals
