On examining the fishes, I found that which had taken the hook, was the _gadus Polachius_, or whiting Pollack. It was about two feet long, and it is probable its active enemy had fastened [p074] on it after it had been hooked; if _before_, it would indicate an extraordinary insensibility to pain in an animal that could attend to the calls of appetite, whilst another was preying on its vitals. The fish which had fastened on the pollack, was the _petromyzon marinus_, or sea lamprey. It was nearly three feet long, and resembled a large eel in shape. Its general colour was a dull brownish olive variegated with bluish blotches; the back darker, and the belly paler, inclining to yellow. The eyes were small, and the mouth large and oval; but when distended, circular. The inside of the jaws was deeply concave, and studded with circular rows of sharp triangular teeth, that issued from corresponding orange-coloured papular protuberances, which formed the gums; the tongue was short and crescent-shaped, furnished with a row of very small teeth round the edge. On the top of the head was a small orifice, or spout-hole, from whence it discharged the superfluous water taken at the mouth. But the circumstance that more particularly distinguished it, was that which gave rise to the vulgar error that it had sixteen eyes. On either side of the neck, commencing just below the real eyes, was a row of seven equidistant spiracles exactly resembling eyes; they are, however, holes lined with a red membrane, and all opening into the mouth, an apparatus to supply the place of gills, whose functions are to extract oxygen from the water, and so perform the office of lungs in aquatic animals. It had two dorsal fins, one on the lower part of the back, narrow, with a roundish outline; the other commencing where the first terminated. The spine was cartilaginous, without processes. The pericardium, containing a small heart, was a remarkably strong membrane, and the liver was as green as grass.