ClipArt ETC
"Tangential section of a larva of Astroides calicularis which has fixed itself on a piece of cork. ec, Ectoderm; en, endoderm; mg, mesogloea; m, m, mesenteries; s, septum; b, basal plate formed of ellipsoids of carbonate of lime secreted by the basal ectoderm; ep, epitheca." — The Encyclopedia Britannica, 1910

Astroides Calicularis

"Tangential section of a larva of Astroides calicularis which has fixed itself on a piece of cork. ec,…

"Vertical section of Aurelia. m., Mouth; st., stomach; r.c., radial canal; R., reproductive organs; g.f., gastric filaments; g.p., sub-genital cavity; l., marginal tentacle; s., sense organ; the shaded part is mesogloea." -Thomson, 1916

Aurelia

"Vertical section of Aurelia. m., Mouth; st., stomach; r.c., radial canal; R., reproductive organs;…

"Diagram showing types of canal system. --After Korschelt and Heider. The flagellate regions are dark throughout, the mesogloea is dotted, the arrows show the direction of the currents. All the figures represent cross-sections through the wall. A. Simple Ascon type (Ec., outer layer; En., inner layer; Mg., mesogloea). B. Sycon type, with flagellage radial chambers (r.c.). CC. Leucon type, with flagellate side aisles on the main radial chambers. D. Still more complex type, with small flagellate chambers (f.ch.)." -Thomson, 1916

Sponge Canal System

"Diagram showing types of canal system. --After Korschelt and Heider. The flagellate regions are dark…

"Structure of a Medusoid. ST., Stomach; M., manubrium; V., velum; T., tentacle; C.C., circumference canal; G., gonad; R.C., radial canal; EN., endoderm; EC., ectoderm; MG, mesogloea." -Thomson, 1916

Medusoid Structure

"Structure of a Medusoid. ST., Stomach; M., manubrium; V., velum; T., tentacle; C.C., circumference…

"Diagrammatic representation of development of Oscarella lobularis. Bl., Free-swimming blastula with flagella; G., gastrula settled down. Next figure shows folding of inner layer (En.); Ec., outer layer. Lowest figure shows radial chambers (R.C.); Mesogloea (Mg.); inhalant pore (P.); exhalant osculum (O.)." -Thomson, 1916

O. Lobularis

"Diagrammatic representation of development of Oscarella lobularis. Bl., Free-swimming blastula with…

"Section of a sponge. Showing inhalant canals, flagellate chambers, a gastrula forming in the mesogloea, etc." -Thomson, 1916

Sponge Section

"Section of a sponge. Showing inhalant canals, flagellate chambers, a gastrula forming in the mesogloea,…