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SPOKANE

1801

SPONGES

for the extensive grain-products of eastern Washington. The adjacent country is also rich in farm and dairy products, fruit and live stock, and has valuable quarries of granite. The manufacturing interests include lumber and lumber-products, machine-shops, foundries, flour-mills, cigars, crackers, soap, flour-mills, machinery-works, pottery, mattress, furniture, broom and trunk factories, a cereal-food plant and brick and terra-cotta works. Spokane is a substantial and admirably built city, as regards both residences and business blocks. Some of the notable buildings are the city-hall, Carnegie Library, the county courthouse, St. Luke's Hospital, Masonic Temple, August Paulsen Building, Marshall-Wells Building and Columbia Building. There are more than 70 churches, and the educational facilities are of the best. The 23 brick and stone school-buildings cost over $i,-500,000, and the high school $175,000. It is the seat of Gonzaga College (which cost $500,000), Academy of the Holy Name, Brunot Hall for Girls and St. John's School for Boys. Spokane has all the facilities of a thriving modern city, owns its own waterworks, and has good drives and parks. The first settlement was made in 1872, the city incorporated in 1881, and now has a population of 104,402,

Spon'ges, a group of animals intermediate between the protozoa  (which see) and ani-

SPONGES

mals like the hydra and jelly-fishes (coelen-terata). The sponges were formerly regarded as plants, but that was in the days when superficial appearances only were considered. They are distinctly animals, and are usually separated into a distinct sub-kingdom called porifera. Although they have no distinct organs, they are clearly a step above the simplest animals. They are many-celled animals and are composed of two distinct layers. The middle layer (mesoderm) is foreshadowed in them, but is not distinctly developed. All animals

above them have three distinct cell-layers. Sponges are mostly marine, but a single genus (spongilld) of fresh-water sponges is widely distributed, being abundant in the region about Chicago, as well as in other parts of the United States. These fresh-

Vertical section of a fresh-water sponge(spongilla)t showing the arrangement of the canal system. C. ciliated chambers; DP. dermal pores; Ex. excurrent canals; GO. openings of the excurrent canals; PG. paragastric cavity; SD. subdermal cavities; O. oscufum.

water sponges are not often noticed by the casual observer. They are clusters of soft, greenish substance looking like algae. They will, however, shrink when touched, and, if closely watched, a current of water can be seen coming from a crater-like opening in their top. Minute points of lime are formed witnin their substance to serve as a support. They increase by budding and by eggs that are formed in the autumn, and carry the life over to another season. The marine sponges are varied in form, size and complexity, Their skeletons are either limy, flinty or horny. The bath-sponges and slate sponges represent the horny skeletons only. When they are living, the skeleton is covered with sponge-flesh, and they look on the outside something like a piece of liver, or like a piece of tanned kid, but always with some pores opening into them. The limy sponges and the glass - sponges are too hard for commercial use. The sponges are all permeated by branching canals which open by small pores on the surface. These canals lead into larger ones, and, finally, open into chimney-like passages which open outward by an orifice of considerable size. Water carrying oxygen and minute food-particles is continually passing in through the small surface-pores, traversing the system of canals, and passing out through the crater-like opening. Along the passage-way are rounded chambers which are lined by numerous cells provided with ixo,gella. These cells do the feeding. The flagella are hair-like threads of protoplasm that keep waving arid help to produce the currents of water. The simplest sponges are small tubes with many inlets and a single outlet. The more complex sponges have the passage-ways very much branched and usually several outlets. Sponges increase by budding and also by the fcrmation of eggs. The sponges of the Gulf of Mexico, the