Disc jellyfish - Naturalist engraving - Ernst Haeckel, Kunstformen der Natur

Engraving reproduction of: Disc jellyfish

Original title Discomedusae - Scheibenquallen

Pilema Poster - Cnidarians of the class Acraspedes (Acraspedae), Order Discomedusae

Illustration from the book Kunstformen der Natur, which is a collection of artistic lithographs of natural sciences published by the German biologist Ernst Haeckel between 1899 and 1904.

This naturalistic illustration is part of an overall style inspired by Ernst Haeckel, which greatly influenced the emerging Art Nouveau movement at the beginning of the ^20th century. This work, illustrating the impressive beauty and great diversity of the biological world, was complemented by a certain amount of scientific information, some excerpts of which are reproduced below.

This information is over 120 years old and some of it may be outdated!

Scientific classification:

 Cnidarian Phylum (Cnidaria)
Class Scyphozoa (Acraspedae)
Order of Discomedusae (Discomedusae)
Suborder Rhizostomata Jellyfish (Rhizostomae)

Scientific notice (extract) accompanying the poster print of Discomedusae - Disc jellyfish :

The branched umbrella jellyfish shown in this plate have a body structure that is mainly similar to the rhizostomes illustrated in Plate 28. They are distinguished, however, by the varied development of their eight oral arms and the delicate appendages that have developed on their sucking organelles. The umbrella, which is used for swimming, has a radial structure with four irregular rays; in the center of its convex underside (subumbrella) is the disc-shaped stomach, surrounded by the four pairs of interradial gonads. From the stomach, 8 to 16 radiating canals branch off toward the free edge of the lower surface of the disc, creating a network of finely branched canals. Within the invaginations of the lobed mantle are the eight rhopalia or statocysts, each consisting of a sensory pit, an eye, and an auditory vesicle (or balance organ). The capturing filaments or tentacles, located on the edge of the umbrella of other medusae, have disappeared in rhizostomes as a result of reduction. In the latter, the capturing organs are most prominently developed on the eight robust oral arms, formed by the bifurcation of the four original (perradial) oral lobes. Since the center of the mouth of all rhizostomes grows in youth and the folds of the oral arms also branch considerably, thousands of small mouth openings form on their free surface, guiding the food to the stomach by fine canals. The distinctive features of the resulting "sucking organelles" are rarely simple (as shown in Figs. 6, 7), more often highly branched, folded, and developed into cauliflower-like formations. In the family Velemdae (Fig. 1-5), the sucking organelle of each arm is divided into two parts, an upper float (scapulae) and a lower float (terminae); the latter is often adorned with small crystalline appendages or other attachments. --- If you need more details or clarification on a specific part of the text, please let me know!

Species present on the naturalist plate of Disc jellyfish - Pilema :

• Pilema giltschii
• Rhopilema frida
• Brachiolophus collaris
• Cannorrhiza connexa