BeschreibungBritannica 1911 Arthropod blood-sinus and heart development.png	Anatomical diagram showing Arthropod blood-sinus and heart development
Datum	veröffentlicht 1893
Quelle	Encyclopædia Britannica (11th ed.), v. 2, 1911, p. 674
Urheber	Edwin Ray Lankester, Q. J. Mic. Sci. vol. xxxiv., 1893
Genehmigung (Weiternutzung dieser Datei)	Public domainPublic domainfalsefalse This image comes from the 13th edition of the Encyclopædia Britannica or earlier. The copyrights for that book have expired in the United States because the book was first published in the US with the publication occurring before January 1, 1929. As such, this image is in the public domain in the United States.

Caption:

Diagram to show the gradual formation of the Arthropod pericardial blood-sinus and “ostiate” heart by the swelling up (phleboedesis) of the veins entering the dorsal vessel or heart of a Chaetopod-like ancestor. The figure on the left represents the condition in a Chaetopod, that on the right the condition in an Arthropod, the other two are hypothetical intermediate forms.