Eudorina elegans was described by the German biologist Christian Gottfried Ehrenberg in his Lectures at the Academy of Sciences in Berlin in the years 1830–1836 (Vorträge in der Akademie der Wissenschaften zu Berlin im Jahre 1830-1836). With the help of Google Translate, here’s what he had to say about it (page 17):
I have also found an eye-shaped form in the family of the epigones, or of the mucous, intestinal infusoria, which have a hairy body. This form of infusoria is also undefined, but it is confused by me, and probably by all previous observers, with Pandorina Morum (Volvox Morum Müller); Less accurate observers also thought they were probably Volvox Globator. I found them in the basin of the animal garden in the spring of this year between conferences. It is quite consistent with the same form, as I see from my drawing made in the Ural, that the animal which I, as Pandorina Morum, from Kyschtym, have doubtless listed in my list of the Russian Infusoria, and I am of the opinion that I had at that time only overlooked the unsuspected eye. The body consists of a gelatinous, globule-shaped sphere, in which a certain number of spherical, green-colored animals are enclosed, each showing a beautiful red, round but small eye, and a simple, long, whirling, or supporting eyelash through the water. The whirling is seen very clearly as soon as a fine, turbid substance is added to the water. To this animal, which is one of the most beautiful infusoria, I have given the generic name Eudorina, in consideration of the closely related eyeless genus Pandorina. The only known species I have called Eudorina argus (beautiful green eye ball).