Page:The American Cyclopædia (1879) Volume XIV.djvu/833

 'SGEAVESANDE legnano), and gave up all his rights to it on condition of receiving a pension, and went to France. VI. Francesco II., younger brother of the preceding, born in 1492, died Oct. 24, 1535. In 1522 he received the duchy in fief from the emperor Charles V., but made him- self odious by imposing onerous taxes. He left no issue, and the duchy reverted to Charles V. 'SGBAVESANDE. See GBAVESANDE. SHACKLEFORD, an unorganized N. W. county of Texas, intersected by the Clear fork of the Brazos river; area, 900 sq. m. ; pop. in 1870, 425, of whom 55 were colored. Stock raising is the chief occupation. SHAD, a well known fish of the herring fam- ily, of the genus alosa (Cuv.), differing from the herrings proper (clupea) in having the cen- tre of the upper jaw deeply notched. The lower jaw is the longer ; the teeth are small and deciduous, in the jaws only ; the air blad- der is simple, opening from the stomach. The genus comprises more than 20 species, among which are the alewife, blue-back, menhaden, and shad herring. The American shad (A. prasstabilis, De Kay, or A. sapidissima, Storer) attains a length of about 20 in., and varies in weight from 2 to 6 Ibs. ; the upper parts of the SHAD 807 American Shad (Alosa prsestabilis). sides and gill covers are coppery, lower part of sides silvery, abdomen pearly, and top of head and back bluish ; a more or less distinct black blotch at the posterior angle of the gill cover ; irides silvery ; dorsal on anterior part of back, quadrangular, transparent, and shutting in a groove ; pectorals and ventrals small, and anal low and partly received in a groove; caudal deeply forked, with a patch of small scales and two membranous appendages at its base ; scales large, and abdominal ridge serrated. They come from the south to deposit their spawn, running up the rivers from the sea ; they ap- pear at Charleston in January, at Norfolk in February, at New York by the end of March or beginning of April, at Boston by the end of April, and in the bay of Fundy by the middle of May. They appear in the Massachusetts rivers early in May, the greatest run being when the apple trees are in full blossom ; the shad fly (hemerolius) appears at the same time, covering the houses and fences; the old return to the sea in August, and the young, 3 or 4 in. long, migrate in September. It is a common belief that the life of the shad is limited to a single year. The Massachusetts fish commis- sioners in 1874 hatched great numbers of shad in the Merrimack river at North Andover. The number caught there in that year was 1,680, which furnished 6,249,000 spawn; of these 3,500,000 were hatched and distributed in vari- ous waters of the state. The average of the yield of eggs was 10,278 to each female. For other efforts toward the propagation of shad, see Fisn CULTURE, vol. vii., pp. 219 and 222. In the Delaware and Hudson rivers, whence New York is mainly supplied, the shad fishery is prosecuted by drift and stake nets, and its commercial value is considerable. The fish are with us mostly eaten fresh, and are delicious, the only drawback being the innumerable bones ; they lose their flavor the longer they remain in fresh water. They will rise to a gaudy fly in fresh water, and afford very exci- ting sport. Their food in salt water consists principally of worms like the shad or sing worm, and shrimps. The shad fishery is of considerable importance to the British prov- inces ; in the upper part of the bay of Fundy, on the New Brunswick side, the fishing is mostly carried on in the channel by drift nets from 25 to 30 fathoms long, sinking to a depth of about 16 ft., with meshes of 4J to 5 in. ; it continues from July to the middle of Septem- ber ; the fish are split and salted, and mostly used in the neighborhood. Shad are some- times caught in standing weirs set on the flats, but these soon destroy the fishery, as fish of all sizes are taken ; in standing nets many fine fish are lost by falling out unless narrowly watched. Stake nets are each about 100 fath- oms long, set on stakes or poles about 15 ft. apart on the mud flats, and are dry at low water ; most of the fish in these are caught on the ebb tide. This fishery is also of impor- tance on the Nova Scotia side of the bay of Fundy ; shad are also taken in the gulf of St. Lawrence. The hickory shad (A. lineata, Sto- rer) is about 15 in. long, silvery on the sides, with six or eight indistinct bluish longitudinal bands; it is lean, and is not used for food. The European shad (A vulgaris, Val.) ascends the Thames and the Severn, the Elbe, Rhine, Seine, Loire, Garonne, Volga, and other rivers, from the Atlantic and other seas, in numerous troops during the spring, varying greatly from year to year. It attains a length of 2 to 3 ft., and is dark green above and silvery below, with a dusky patch behind the gill covers ; its flesh is little esteemed in England. Cuvier and Yarrell describe the A.finta, the twaite shad or May fish, about 14 in. long, with teeth in both jaws and seve'ral black spots on the sides, and a dry insipid flesh. Valenciennes maintains that this is only the young of the A. vulgaris before the teeth have fallen, and declares that only one species is found in the waters of Europe. The head of the shad presents a good example of the water tubes through which, in many fish- es, fluid is introduced into the blood and the system generally; the object of this appara- tus, often very extensive, is commonly said to be for accommodating the body to the pres- sure of different ocean depths.