Cystoids - Detailed illustration from nature - Ernst Haeckel, Kunstformen der Natur

Engraving reproduction of: Cystoids

Original title Cystoidea - Beutelsterne

Poster of Callocystis - Starfish of the class Cystoidea (Cystoidea)

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This information is over 120 years old and some of it may be outdated!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

 Phylum Echinoderms (Echinoderma)
Main class of Monorchonia
Class Cystoidea

Scientific notice (extract) accompanying the poster print of Cystoidea - Cystoïdes :

Cystoids, or "sea sacs" as they are sometimes called, lived exclusively during the Paleozoic Era, several million years ago; we therefore know of these extinct starfish only from their fossils (as do crinoids, Table 95, and blastoids, Table 80). Like these latter groups, cystoids lived exclusively on the sea floor, often attached to a segmented axis. Their sac-like, often almost triangular, body is protected by strong calcareous plates and usually has three openings. The upper opening (opposite the axis) is central and represents the mouth; the other two openings are centered on the same side. The larger lower opening is the anus (often pyramidal, closed by 5 to 6 valves), while the smaller opening, between the mouth and the anus, is the gonopore (genital opening). The mouth of cystoids is surrounded by a crown of tentacles or ambulacra (anthodium), usually composed of five band- or leaf-like rays (the ambulacra); more rarely, there may be four (Fig. 1), three (Fig. 9), or two (Fig. 6). Each field of tentacles or ambulacrum is composed of an external feeding groove (subvector) and a suite of internal water canals or the associated ambulacral system. The center of this canal system is a ring of hydraulic vessels (hydrocirceus) surrounding the mouth, which captures seawater through an external opening, the hydraulic pore (hydropore), for feeding the canals. The radial canals or "berrovial canals" (usually five in number), extending from the annulus canal, radiate a short or long distance from the theca (box) and provide temporary pathways for the mobile digits, often arranged in two rows along the feeding furrows and covered with small plates. Food is conveyed to the mouth by ciliary movement through the subvectors. All the cystoids represented here, natural size or slightly enlarged, have been found fossilized in the Silurian mountains, mostly in Russia and North America.

Species present on the naturalist plate of Cystoïdes - Callocystis :

• Staurocystis quadrifasciata
• Glyptosphaera leuchtenbergii
• Protocrinus fragum
• Cystoblastus leuchtenbergii
• Pseudocrinus bifasciatus
• Sycocystis angulosa
• Callocystis jewetti
• Hemicosmites extraneus
• Glyptocystis multipora
• Glyptocystus pentapalma
• Chirocrinus testudo
• Caryocrinus ornatus
• Agelacystis hamiltonensis
• Agelacrinus vorticellatus