Translation of the original German introduction by Ernst Haeckel:
Phylum of Vertebrata (Wirbeltiere); - main class of Gnathostoma (Kiefermäuler); - class of Pisces (Fische); - subclass of Teleostei (Knochenfische).
In the centre of the plate four distinct species of ‘bony fish’ are seen which are markedly distinguished from the usual ‘teleos-animals’ due to their peculiar shape. This group, imagined as swimming in the ocean, is surrounded by a corona of twelve fish scales that are presented at low magnification; they are supposed to give an impression of the delicate shape and characteristic structure of these bony skin formations.
The scales of these fishes are thin bone-panels that are formed in distinct folds of the ‘leather skin’, the so-called “scale-pouches” by connective tissue cells. Three main forms are distinguished that are fundamentally distinct for the respective three subclasses of real fish. The oldest or ‘original fish’ (Selachii): the principal forms of the entire class as well as modern sharks and ray belong here; their sturdy skin is consistently covered with Placoid-scales, structurally resembling the teeth of the mouth cavity, therefore also called “main teeth”. ‘Ganoid-scales’, ‘melted scales’ or ‘shiny scales’ of the ‘melt-fish’ (Ganoides) originate from the ossified papilla of the ‘leather skin’ through the stronger development of the ‘melted coating’. The younger, during Jurassic period appearing bony fish (Teleostei) originate here with the vast majority of today’s fishes belonging to them. Their body is usually covered with thin, transparent ‘glassy scales’ or ‘Diaphan-scales’ that already developed within a part of the younger Ganoids through regression of ‘melted scales’. However, there are also diverse families of bony fish with their skin not being covered with common glass scales but with bigger ‘bony panels’. This is the case in box fish (Ostraciontes, plate 42) as well as in the three bony fish of our plate 87 (fig. 1, 2, 3).
Diaphan-scales of the common bony fish (fig. 5 to 16) are usually most thin, transparent and flexible bone-platelets of elongated-rounded or almost quadrangular shape, structured in regular longitudinal and transversal rows. With theie posterior, free ends they cover the body like roof-tiles (in the direction front to back) while their anterior or basal part is fixed in the scale-pouch of the ‘leather-skin’. Most Diaphan-scales show a characteristic sculpture of the exterior surface, a system of radial-converging strips or fillets (radial ribs) and more delicate, concentric transversal strips (transversal ribs) that cut through them. The radial strips usually emerge from an eccentric crest that rests close to the center of the posterior free rim, more rarely in the center of the scale (fig. 2, 3). Cycloid and ctenoid glass-scales are distinguished as two main divisions of Diaphan-scales. Most of the shapes illustrated here are ‘comb-scales’ (Ctenoides); their posterior free end is tenderly dentate or comb-like studded with numerous quills and prongs. It is smooth, however, and rounded in the common ‘round-scales’ (Cycloides). At times even the outer, free surface of the scales is dentate (‘rasp-scales’, Spariodes, fig. 13).
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.