Now we revert to the grouse-birds, a family for which the zoologist's name is Tetraonidæ. They all have the beautiful crimson arch of bare knobby skin above each eye which gives its chief beauty to our grouse. The family contains several genera and included species. The largest species is the capercailzie (a Gaelic word), or cock of the wood, called by the French "coque du bois," by the Germans "auerhahn" (auerhuhn for the hen bird), and by the Norwegians "tiur." It is placed in the genus Tetrao (which gives its name to the "family"), and receives the specific name "urogallus." This fine bird was formerly native in England, as well as in Scotland and Ireland, and is found in the pine forests of Europe from Spain to Lapland and Greece. It has been re-established in Scotland since 1838. An allied species is found in Siberia. The black grouse (often called black cock and grey hen) is a second species of the genus Tetrao, namely, T. tectrix. It is often called "Lyrurus tetrix." The French name for it is "coq de bruyère"; the German is "birkhahn." It is a smaller bird than the capercailzie, but frequently produces hybrids with that species. The beautifully curled tail-feathers are favourite adornments for the hat of mountaineers and hunters in the Tyrol and Switzerland. Though the word "grouse" may have been first applied (as some think) to the black cock, it is now the proper appellation of the red grouse. This bird is placed by zoologists in the genus Lagopus--the members of which are easily distinguishable from other Tetraonidæ by the fact that their feet and toes are well covered with feathers. "L. scoticus" is the scientific name of the red grouse. Being a purely British bird, it has no foreign designations. "L. saliceti" is the name of the allied willow-grouse, which has an endless variety of names, owing to its great range of distribution. The willow-grouse is often called ptarmigan, and is sold as such to the number of thousands by poulterers in our markets, but it is not the true ptarmigan. Owing to the fact that its plumage is quite white in winter, there is much excuse for the confusion. The name "ptarmigan" is the Gaelic word "tarmachan," and no one has explained how the initial "p" came to be added to it. The bird called in Scotland tarmachan or ptarmigan is a third species of Lagopus. It is much rarer in Scotland than the red grouse, and lives in high, bare ground. It is numerous at an elevation far above the growth of trees in Norway, and occurs also in the Pyrenees and the Alps. It turns white in winter (as do all the species of Lagopus except the red grouse), and differs in many features of structure from the red grouse and the willow-grouse. It is called "L. mutus." A fourth species of Lagopus is L. rupestris, of North America, Greenland, Iceland, and Siberia. Spitzbergen has a fifth species, L. hemileucurus, a large form. The sixth and smallest species of Lagopus is the L. leucurus of the Rocky Mountains.