A. Primordialis Small 114×320 Medium 228×640 Large 365×1024 Download Tiff Original 855×2400 | (488.1 KB) Description "Simple sponge (Ascetta primordialis). Note the vase-like form, the apical osculum, the inhalant pores in the walls." -Thomson, 1916 Keywords apical osculum, Ascetta primordialis, inhalant pores, porifera, simple sponge, sponge walls Galleries Sponges Source: J. Arthur Thomson, M.A., LL.D. Outlines of Zoology (New York, NY: D. Appleton & Company, 1916)