Leopold Blaschka (1822-95) was a Czech jeweller working in Dresden who turned his attention to his passion: natural history. His glass models of plants and sea creatures were highly prized and commissioned by several universities and natural history museums of the late 19th century, where indeed almost all extant examples of his (and his son's) work survive. We know of only one other glass jellyfish in private hands.
The need for a glass didactic models of these jellyfish is that their soft bodies are incredibly difficult to preserve, and when suspend in jars with fluid loose their colour quickly and are thus not a good representation of the appearance of the animal in life. Coloured and translucent glass is of course the perfect material to use, but the difficulty of working in the medium is such that the quality of the Blaschkas work has never been equalled since.