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

Reproduction engraving of: Ascidiacea

Original title Ascidiae - Seescheiden

Cynthia's poster - Tunicates (Tunicata) of the class Ascidians (Ascidiae)

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This information is over 120 years old and some of it may be outdated!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

 Kingdom of the Tunicates (Tunicata)
Class Ascidiidae (Ascidiae)

Scientific notice (extract) accompanying the poster print of Ascidiae - Ascidiacés :

Tunicates (Tunicata) occupy an independent position among invertebrate animals; they were formerly classified sometimes among the Molluscs, sometimes among the Worms (Vermalia). However, recent studies of their embryonic development have led to the conviction that they are closely related to the Vertebrates (Vertebrata) and that they share a common origin with them. The juvenile stages of both groups (called Chordula) have the same characteristic body structure, absent in all other invertebrates. Tunicates live exclusively in the marine environment, either as sessile individuals (Ascidiacea) or free-swimming (Thaliacea). Ascidiacea, or "sea squirts," live either singly, as single individuals (Monascidiae, Fig. 1-4), or by budding into colonies composed of many individuals (Synascidiae; Fig. 5-14). Monascidiae, or "simple sea squirts," generally have the shape of an elongated sac that attaches to the seabed and has two openings close to each other: a larger one, the mouth, and a smaller one, the cloacal siphon; the mouth is surrounded by a crown of tentacles or cilia (Fig. 2). The tunic, which surrounds the soft body, is composed of cellulose and is sometimes covered with spines (Fig. 1). By incising the tunic and separating the right and left halves of the body, it can be seen that most of the body cavity is occupied by a pleated pharynx, which opens at the top through the mouth (Fig. 3). Below, this "branchial pharynx" extends into the esophagus and stomach, which then open into the mantle cavity through the anus. This cavity also receives the sexual products, produced by a lower hermaphroditic gland, and expels them through a cloacal opening at the top. The colonial individuals, which form the colonies of Synascidiae, are rarely distributed evenly (Fig. 5); they usually form smaller groups, clumps, or cormidia (Fig. 6-14). Within each star-shaped cormidium, the individuals are grouped radially, their mouths directed outward and their cloacal siphons toward a common central point (Fig. 8) or fused into a common "cloacal opening" (Fig. 7). The surface of the tunic of these Synascidiae is often beautifully colored and variegated.

Species present on the naturalist board of Ascidiaceas - Cynthia :

• Cynthia melocactus
• Molgula tubulosa
• Fragarium elegans
• Polyclinum constellatum
• Synoecum turgens
• Botryllus polycyclus
• Botryllus rubigo
• Botryllus marionis
• Botryllus helloborus
• Polycyclus cyaneus
• Botrylloides purpureus