The most troublesome quadruped is the wild dog, which chiefly attack pigs and other small domestic animals. Mice are probably the greatest pest of the island, but they are considerably kept down by their natural enemies, the snakes. The latter not infrequently reach a length of from six to nine feet. There are a good many mosquitoes, but they are no worse than they are in New Jersey. Numerous species of ants and bees exist as well as fireflies. The latter occasionally fly in great masses, producing beautiful effects in the tropical nights. It may be stated that, on the whole, Porto Rico is singularly free from those noxious reptiles and insects which seem to inherit the rest of the West Indies as their peculiar possession. Immense pastures occupy a part of the lowland, and feed large herds of cattle of an excellent quality. St. Thomas and the French islands all obtain their butcher's meat from Porto Rico. Even Barbadoes comes there for cattle. Sheep always thrive in a hot country, and they grow big and fat in Porto Rico. Fresh lamb and mutton are constantly shipped from there. A very numerous class of the people are shepherds, and these live upon mutton and the kind of highland rice, already alluded to, which is very easily prepared for food. Poultry is most abundant, and the seas and rivers are full of the finest fish. Agriculture has hitherto been almost exclusively in the hands of the natives, but most of the business and commerce have been controlled by foreigners and Spaniards from the Peninsula. Although the island is certainly well developed agriculturally, it certainly admits of considerable expansion in this direction. Under a different political system, and when it is freed from the oppressive and vexatious taxation, Porto Rico will certainly become far more productive and prosperous even than it is now. There is no question but that the island, richly endowed as it is by Nature, has been miserably governed. But agriculture in the near future will certainly not be the main industry of the island. For there are known to be gold, copper, iron, zinc and coal mines, which have never been developed. In fact, strange as it may appear, none of these valuable mines is worked at all. The vegetable productions have been considered so valuable that in order to cultivate them the minerals have been neglected. There are also extensive sponge fields, which are very valuable, but which have not been touched, owing to several causes, chiefly the lack of capital. The same can also be said of the quarries of white stone, granite and marble. Then there is the question of salt, which is sure to be of importance. There are large quantities of salt obtained from the lakes. Salt works have been established at Guanica and Salinas, on the south coast, and at Cape Rojo, on the west. This constitutes the principal mineral industry of Porto Rico.