Page:The New International Encyclopædia 1st ed. v. 18.djvu/536

SPONGE. 462 SPONTANEOUS GENERATION. ranean. Spongia gossypina, the wool sponge of Florida and the Bahamas, corresponds to Spongia equina, the horse or batli sponge of the Mediter- ranean. This wool sponge of Florida attains under favorable circumstances a weight of one- tenth pound, in six months, and reaches a size of commercial value in a year. Fossil sponges are known in rocks of all ages. They appear first in the Cambrian as Proto- spongia and Archjroscyphia, representing the hexactinellids and lithistids. They are repre- sented in the Ordovician by the curious Brachio- spongia, and a number of irregular forms; in the Silurian by Astrceospongia, Astylospongia ; in the Devonian by Ilindia and the Dictyospongi- dfe, which latter enjoyed- such great expansion in the shallow seas of western New York during Chemung time. Receptaculitcs is a peculiar sponge that is common in the Ordovician. Dur- ing the Mesozoic sponges attained a great de- velopment, became especiall_y abundant during the Cretaceous period, and declined during the succeeding Tertiary. Noteworthy Cretaceous genera are Ventriculites and Cceloptychium. BiBLiOGKAPHY. Hyatt, "Revision of North American Poriferse," in Memoirs Boston Society of Natural History (vol. ii., Boston, 1875) ; Eauif, "Paloeospongiologia," in Pakeontographica, vol. xl. (Berlin, 1803); Hinde, Catalogue of Fossil Sponges of the British Museum (London, 1883) ; Hall and Clarke, "A Memoir on the Paleozoic Reticulate Sponges Constituting the Family Dictyospongidse," in Memoirs of the New York State Museum, vol. ii. (Albany, 189S). SPONGIOZOA (Neo-Lat. nora. pi., from Gk. <rjro-)-,ia, Sjwngia. sponge -- iqxip, zOon, animal). One of the branches or phyla of Invertebrates, in- termediate between the Protozoan and the Coelen- terati, and represented by a single class, Parifera, which comprises the sponges. SPONSORS (Lat. sponsor, surety, from spon- dcre, to promise; connected with Gk. (rnivSeiv, sprndein, to pour a libation). The persons, also called godfathers and godmothers, who present a, candidate for baptism, and in the Roman Catholic Church for confirmation also, to the minister of those sacraments. In the case of infants they are representatives who make the vows the child is incapable of making; with adults they act rather as witnesses, and among their duties is a subsequent general oversight in spirit- ual matters, with a view to preserving religious life in their godchildren. The spiritual bond resulting from this relation is supposed by Roman Catholic theologians to constitute a species of affinity, and hence an impediment of marriage, extending to the parents of the bap- tized, and even at one time operating between the sponsors themselves. SPONTANEOUS COMBUSTION (Lat. spon- taneusK willing, of one's own accord, from sponte, abl. sg. of *spons, will). The ignition of sub- stances at a given moment apparently without the intervention of any causative agency. The spontaneous combustion of organic materials is a frequent cause of fires. hen large quantities of soot, linen, paper, cotton or woolen stuffs, ship's cables, etc., are soaked with relatively small amounts of oils (especially dr.ying oils) and ex- posed to a limited access of air, they may be ex- pected to take fire sooner or later. Similarl.v, trimmings of lamp-wicks have been known to take fire if kept in open boxes. The presence of moisture frequently aids spontaneous combustion, and piles of damp hay, freshly mown grass, some- times take fire spontaneously. The phenomenon is not, however, without a clearly defined cause. Fats and oils can be shown to undergo a slow pro- cess of combustion at but slightly elevated, if not at the ordinary, temperatures. This fact may be demonstrated by placing a little oil on a hot (but not red-hot) metallic surface, when the combustion of the oil will caiise a peculiar odor and will render the oil faintl.y luminous in the dark. The combustion of a small amount of oil causes the evolution of a corresponding amount of lieat; the consequent rise of temperature ac- celerates the combustion, and lience produces a further elevation of temperature, and so forth, until at a given moment the temperature may become so high as to cause the inflammation of the oil, and with it of the entire mass of organic material containing it. The more porous the ma- terial, the greater the surface nf oil exposed to the air, provided the amount of oil is not large enough to fill the pores completely. Free ac- cess of air might prevent spontaneous combus- tion by effecting a lowering of the temperature; nor could combustion take place if too little or no air at all were admitted. As to the spontaneous combustion of human bodies, it is an impossibil- ity, and all reports of such cases can be clearly shown either to be due to erroneous observation or to be intentionally fraudulent. See Ptro- PHORU.S. SPONTANEOUS GENERATION and PRO- TOGENESIS. The doctrine that different forms of life, especially the lower, have arisen by phy- 6PONGE STRUCTUnE. 1. Exterior of a living bath-spnnge: the arrows eliow how the water is euclied into the email pores and ex- pelled from the elevated canai-raouths (oscules). 2. Diagram of canal eystem, represented by a yonnp: sponge with a single escurrent orifice; such a ejstem is represented in a large sponge by each oscnle: a, o.scxile; 7>. inhalent pores. 3. Vertical section of a part of a bath-sponge: h, inhalent pores; c, canals; d, d, flagellated chambers; e, f. skeleton fibres: ff, maturing eggs. 4. Enlargedview of a "part of the canal system: a. inhalent pores and passages by which water is drawn into the spherical "flagellated chambers and their connecting passages (apopyles) conducting it into larger spaces [b) whence it flows out through an oacule (c). Cf. Fig. 2. 5. Enlarged view of flagellated cells lining the chambers and canals; and a single cell: d. nucleus; c, contractile Teelcle; m, collar: f. flagellum. 6. Various forms of siliceous spicules. 7. One form of siliceous fibrous skeleton. 8. Fresh-wat<>r sponge: vertical section of Spongilla; the water enters through the dermal pores (a) into the Bub-dermal cavities ifA, then enters the incnrrent pores and passages (c. colored black), and passes into flagellated chambers (d). thence out through the excurrent canals (e). into the main central canal or perigastric cavity if). in which the openings (g) of these canals from all sides are indicated by the black dots; and the water is finally discharged through the apical oscule (h). 9. A bath-sponge (Spongia). 10. A branching sponge {utialinopsillii, oculata,), a 'finger' sponge, common on the Atlantic coast of the United States.