Perhaps the most singular in habit of any sponge is /Cliona sulphurea/, the boring-sponge, a common species found from Cape Cod to South Carolina and abundant in Long Island Sound. It [pg106] is bright sulphur-yellow in color, grows in irregular masses of considerable size and fine texture, and has low wart-like prominences. It lives on shells spreading over both surfaces, at first forming little burrows, but eventually penetrating the shell in every direction, honeycombing and at last completely destroying it by absorption. Sometimes it settles upon living shells and greatly irritates the animal, which constantly secretes new lime to cover the perforations in its shell. These sponges are an important factor in the economy of the sea, as they disintegrate dead shells, which would otherwise accumulate in vast quantities. SUBCLASS =CALCAREA= GENUS ^Grantia^ ^G. ciliata.^ Small, urn-shaped or oval, with large aperture at the summit, surrounded by a circle of projecting spicules. It is found in tide-pools and on piles of wharves from Rhode Island northward. GENUS ^Leucosolenia^ ^L. botryoides.^ Tubular, branched. Occurs in the same places as /Grantia ciliata/. SUBCLASS =NON-CALCAREA= GENUS ^Suberites^ ^S. compacta.^ Elongated, compressed masses, sometimes in several lobes; attached by one edge; texture fine, firm, compact; surface smooth; color bright yellow. It grows on sandy bottoms, and is common in shallow water south of Cape Cod. (Plate XXXVIII.) GENUS ^Polymastia^ ^P. robusta.^ When young it forms yellowish-white incrustations over shells and stones; later it grows into long, slender, round, tapering, finger-like projections. Found on the northern New England coasts in deep water. GENUS ^Cliona^ ^C. sulphurea^, the boring-sponge. Irregular massive form of firm texture; surface covered with scattered low wart-like prominences about one eighth of an inch in diameter; bright sulphur-yellow. It destroys, by absorption, vast quantities of dead shells. [Illustration: PLATE XXXVIII. Halichondria panicea. Suberites compacta. Hircinia campana. Esperiopsis quatsinoensis (found on the sea-beaches of Alaska).] [Illustration: PLATE XXXIX. Microciona prolifera. Chalinopsilla arbuscula. Chalinopsilla imitans. Euspongia officinalis, var. tuba. Chalinopsilla oculata.] GENUS ^Microciona^ ^M. prolifera.^ When young this species forms bright-red incrustations over shells and stones; later it rises into irregular lobes and tubular prominences. When fully developed it is profusely branched in a forking manner. The branches are more or less flattened, and often are palmate at the ends. It grows in clusters six inches in diameter, of a dark orange-red color. When dry it is grayish-brown, brittle, and bristly. It is found from Cape Cod to South Carolina, and is abundant in Long Island Sound. (Plate XXXIX.) GENUS ^Tedania^