TY - JOUR TI - Compartments in Scyphozoa AU - Berking, Stefan AU - Herrmann, Klaus T2 - The International Journal of Developmental Biology AB - Polyps of Scyphozoa have a cup-shaped body. At one end is the mouth opening surrounded by tentacles, at the other end is an attachment disc. The body wall consists of two tissue layers, the ectoderm and the endoderm, which are separated by an extracellular matrix, the mesoglea. The polyp's gastric cavity is subdivided by septa running from the apical end to the basal body end. The septa consist of two layers of endoderm and according to biology textbooks the number of septa is four. However, in rare circumstances Aurelia produces polyps with zero, two, six, or eight septa. We found that the number was always even. Therefore we propose that two types of endoderm exist, forming alternating stripes running from the oral body end to the aboral end. The stripes have some properties of developmental compartments. Where cells of different compartments meet, they form a septum. We also propose that the ectoderm is subdivided into compartments. The borders of the ectodermal and endodermal compartments are perpendicular to each other. Tentacles of the polyp and rhopalia (sense organs) of the ephyra (young medusa), respectively, develop at the border between two ectodermal compartments. The number can be even or odd. Rhopalia formation is particularly favored where two ectodermal and two endodermal compartments meet. PY - 2007 DO - 10.1387/ijdb.062215sb VL - 51 IS - 3 SP - 221 EP - 228 J2 - Int. J. Dev. Biol. LA - en SN - 0214-6282 SN - 1696-3547 UR - https://ijdb.ehu.eus/article/062215sb Y2 - 2024/11/24/06:49:02 ER -