FISHES 22. Trout. Salmo trutta, Linn. Generally distributed in running waters, and found even in small brooks. The American charr, Salmo fontinalis, Mitchell, has been in- troduced near Guildford. 23. Herring. Clupea harengus, Linn. Young specimens occur in the tidal part of the Thames. Dr. Giinther has shown that the ' whitebait ' eaten in London between April and July consist mainly of young her- rings. 24. Shad. Clupea alasa, Linn. 25. Thwait. Clupea Jinta, Cuv. This and the preceding species enter rivers in the spring, and a few have been found in the Thames as far as Hampton Court. APODES 26. Eel. Anguilla vulgarity Turt. CYCLOSTOMES 27. Lampern. In rivers. Petromyzon fluviatilis, Linn. 28. Mud Lamprey. Linn. Petromyzon branchialis. In rivers and brooks. 199
