General physiology; an outline of the science of life . A B Fig. 267.—Silicious skeletons of Radiolaria. (After Haeckel.) A, Dorataspis. B, Theoconas. (Fig. 265, //), which play so great a role in the silicious andcalcareous skeletons of sponges, must take place when severalspherical bodies are in contact with one another and a skeleto-genous substance, such as calcium carbonate or silicic acid, isexcreted into the fine spaces between them (Fig. 265, I). LatelyDreyer (92) has extended the same idea to several specialexamples, and has shown how various and often extremelycomplex skeletal parts,
General physiology; an outline of the science of life . A B Fig. 267.—Silicious skeletons of Radiolaria. (After Haeckel.) A, Dorataspis. B, Theoconas. (Fig. 265, //), which play so great a role in the silicious andcalcareous skeletons of sponges, must take place when severalspherical bodies are in contact with one another and a skeleto-genous substance, such as calcium carbonate or silicic acid, isexcreted into the fine spaces between them (Fig. 265, I). LatelyDreyer (92) has extended the same idea to several specialexamples, and has shown how various and often extremelycomplex skeletal parts, especially in the Radiolaria, may easilybe traced to the excretion of skeletogenous substance in theprotoplasmic walls of a vacuolar layer (Fig. 266). Thus, accordingto the form of the vacuoles, the thickness of their walls, the placeat which the secreted skeletal substance is deposited, and itsquantity, a great variety of skeletal forms must result, and areactually realised in the richly varied forms of the radiolarian 544 GENERAL PHYSIOLOGY skele
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Keywords: ., bookcentury1800, bookdecade1890, bookidgen, booksubjectphysiology
