Description: English: Figure 4. Aspects of the Gastropore and Gastropore Tube. (A) Sporadopora dichotoma, USNM 52647, a flush gastropore and several smaller flush dactylopores, (B) Stellapora echinata, USNM 59945, a stellate gastropore, (C) Lepidopora sp., BM 1890.4.11.24, a broad abcauline gastropore lip, (D) Distichopora uniserialis, USNM 15969, horizontal tabulae in axial gastropores, (E) Crypthelia formosa, USNM 60084, double-chambered gastropore tube, female ampullae in ring around cyclosystem with an open efferent pore at base of lid, (F) Crypthelia robusta, NZOI P-919, double-chambered gastropore tube showing ring constriction, (G–I) Adelopora pseudothyron, USNM 60128, gastropore operculum showing the closed type of opercular articulation, in the closed and open position, and underside of one showing an articulating nub, respectively, (J) Same as G–I, an operculum bored by a predator, (K–L) Adelopora fragilis, MNHNP, an example of the open opercular articulation. Date: 21 March 2011. Source:
https://dx.doi.org/10.1371%2Fjournal.pone.0021670. Author: Cairns, S.D. 2011. Global Diversity of the Stylasteridae (Cnidaria: Hydrozoa: Athecatae). PLoS ONE. 6(7): e21670. DOI: 10.1371/journal.pone.0021670.