What printer is this? I've been watching this video 3D printing guides: Calibration and why you might be doing it wrong and at the start (at 0:30) three of the first Reprap printers are mentioned (and shown): 


Darwin;
Prusa Mendel, and;
what sounds to be "Cells".


Here is a screenshot:



which, to me, looks like a Mendel.

However, after having looked at:


RepRapWiki - RepRap project, and;
All3DP - The Official History of the RepRap Project


... I can not see the "Cells" printer listed or mentioned. 

Am I hearing it correctly?

Or is it "Sells", in reference to Edward Sells, one of the four authors of RepRap – the replicating rapid prototyper? However, this paper only mentions/shows the Darwin and Mendel printers.
Yes, it is a "Sells Mendel" in reference to Edward Sells. As noted on the RepRap wiki:


  Ed Sells, a student of Dr. Adrian Bowyer, designed and built the first Mendel printer, sometimes called a "Sells Mendel" to distinguish the original design from later tweaks.