Translation of the original German introduction by Ernst Haeckel:
Phylum of Cnidaria (Nesseltiere); - subclass of Craspedotae (Schleierquallen); - order of Leptomedusae (Faltenquallen); - family of Aequoridae (Sonnenquallen).
Aequoridae illustrated on this plate are distinguished from the other Leptomedusae by the considerable size and the unusual number of ‘radiant canals’ that run along the lower plane of the gelatinous umbrella; seen from below (fig. 1, 3) this umbrella resembles a sunflower with multiple petals. Whereas in most other Medusae the number of radial canals amounts to four or eight, here it goes up to 32 – 64 or even beyond hundred. The circular gelatinous umbrella of these Aequoridae is usually flat and disc-shaped (fig. 1-3), more rarely bell-shaped and high-arched (fig. 4-6). The arched upper plane (Exumbrella) is at times pervaded by radial ribs, similar to a crystal plate (fig. 2, 5). Along the grooved lower plane (Subumbrella) the ring muscles are found that contract the umbrella and generate swimming movement by ejecting water from the umbrella cavity. In the centre of the lower umbrella plane the flat, circular gastrovascular cavity is situated; it opens through a very elastic mouth that is surrounded by a corona of thin, flexible mouth lopes (fig. 1, 3). At times the latter sit at the lower end of an inverted conical gelatinous stalk that protrudes considerably at the lower end of the umbrella cavity (fig. 5, 6). ‘Radiant canals’ that originate from the perimeter of the stomach rise along the ‘stomach stalk’, bend outward at the top and move along the subumbrella towards the rim of the umbrella; there they unite to form a ring canal. Along this ring canal the ‘nerve ring’ is also found as well as a corona of ‘hearing bubbles’, still more interior a horizontal ‘swimming ring’ (Velum, fig. 1, 3). Numerous tentacles or capturing threads that leave from the rim of the umbrella start most graceful wave-shaped movements while swimming. Aequoridae are gonochorists like most other Medusae; sexual glands here are small sausage-shaped pouches that produce eggs in females, sperms in males; they lie at times at the entrance of radial canals (fig. 6), at times along or towards the end of the canal (fig. 1, 3, 5). Usually, the colour of the tender, transparent Aequoridae is bluish or light reddish.
Translation by VR Translators Bangalore
We've scanned the original lithography at 1200dpi on the Epson A3 scanner of A3 scanner huren. You can download a 400dpi JPEG here.