Smit Original Early Drawing of Fishes of the Silurian

SMIT, Joseph (1836-1929).
Fishes of the Silurian Period.
Original Illustration in pen, ink and grey wash, heightened in white.
c.1905-1912.
7 1/4" x 10 5/8" sheet.

Original artwork for Henry R. Knipe's Nebula to Man. Illustrated on page 16.

1. Pteraspis (meaning "wing shield") is an extinct genus of pteraspidid heterostracan agnathan vertebrate that lived from the Lochkovian to Eifelian epochs of the Devonian period in what is now Brazil (Eifelian Maecuru Formation), Britain (Lochkovian Ditton Group), Ukraine (Lochkovian Ivane Suite, Pragian Babin Sandstone) and Belgium.

2. Holoptychius is an extinct genus of porolepiform lobe-finned fish from the Middle Devonian to Carboniferous (Mississippian) periods. It is known from fossils worldwide. The genus was first described by Louis Agassiz in 1839.

3. Cephalaspis (meaning "head shield") is a probably monotypic genus of extinct osteostracan agnathan vertebrate. It was a trout-sized detritivorous fish that lived in estuaries of the late Silurian and the early Devonian. Like its relatives, Cephalaspis was heavily armored, presumably to defend against predatory placoderms and eurypterids, as well as to serve as a source of calcium for metabolic functions in calcium-poor freshwater environments. It had sensory patches along the rim and center of its head shield, which were used to sense for worms and other burrowing organisms in the mud.