An atrial membrane, similar to that previously reported (as a placental membrane) in Placentela crystallina Redikorzev, 1913, has been found in the holotype and other specimens of another aplousobranch ascidian, Ritterella tokioka Kott, 1992 (=R. pedunculata Tokioka, 1953). In serial sections, the membrane is seen to be an extensive fold of the atrial epithelium over the rectum that projects into the atrial cavity and supports developing embryos over its outer surface. The similar states in the atrial membrane seen in the two species are attributable to homoplasy, rather than homology.
You have requested a machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Neither BioOne nor the owners and publishers of the content make, and they explicitly disclaim, any express or implied representations or warranties of any kind, including, without limitation, representations and warranties as to the functionality of the translation feature or the accuracy or completeness of the translations.
Translations are not retained in our system. Your use of this feature and the translations is subject to all use restrictions contained in the Terms and Conditions of Use of the BioOne website.