KEYWORDS
Tunicate, Tunicata, Botrylloides, Ampullae, Heart, Chaotic, Entrainment

Abbreviations
amp: ampullae
ATP: adenosine tri-phosphate
SW: sea water
T-type: transient opening calcium channels

Availability of data and materials
Java code for the ImageJ plugin used to measure areas and the resulting data seen in Fig. 7 etc. are available at Github.com in the repository: mwkonrad/BMC_Zoology_1.

Acknowledgements
Not Applicable.

Funding
There was no external funding.

Ethics approval and consent to participate
Not applicable.

Consent for publication
Not applicable.

Competing interests
The author declares there are no competing interests.

Author details
Science Is Art, 3 S 40 Dock, Sausalito CA 94965, USA